David Vizard's PowerTec 10 EP 15 When Flat Lifters Reign Over Roller Lifters

[@autonomous_collective]

David Vizard, one of the world's premier race engine builders, author of over thirty books on racing engines, and magazine tech writer, has developed a revolutionary new "Engine Break-in System" using Oil Extreme's proprietary Calcium Petroleum Sulfonate technology. In David's engine building seminars, he has been so sure of his 8 to 11 extra horsepower claims that he has done before and after dyno tests right on the spot, with the whole class watching. One well known skeptical engine builder, who was doing the dyno test in his shop, came out of the dyno room after the dyno runs, and told the class, "This **** works." The actual gain was 8 Horspower, after using only 1 bottle of the 3 bottle set. This EP (extreme pressure) anti-wear technology is the answer to the low ZDDP levels in today's motor oils. This system eliminates cam wear problems.

[@panzerkfw]

The audio is great. I'm using a real computer with real speakers. People having issues are apparently using headphones or a cell phone or possibly have ADHD. I didn't even know there was background music until I read the comments. When listening for it I kinda like the music.

[@marvingvx1]

Roy, I have more negs than positives here so I am going to cut the loudest down some. Please report you opinion after the next video. DV

[@lancecooper4646]

Point taken with money better spent on a stroker crank, the extra torque would transform the driveability & your "flat tappet provisos" at the end of the video were invaluable 👍

[@87_951]

Holy crap David Vizard!!! What a legend.

[@MF-le7fp]

David, thanks for your time, and sharing your knowledge with us. I built the motor in my 69 Camaro using one of the builds in the back of your SBC Budget book. She runs like a spotted ass ape. 😁👍

[@jubjub905]

Which one did you do?

[@danieldimitri6133]

I figured this out as a teen, a roller needs a concaved lobe base to do what a flat tappet could be ground to do. Strength aside, a small base circle and a large lifter diameter on a flat tappet will lift the valve off the seat faster but the lift and velocity are limited a lot by the lifter diameter at least in a simple profile constructed of 4 radii. You could hypothetically construct a lobe with some parabolic or elliptical shape or at least something that resembles those shapes but is geometrically constructed of line segments that follow the ideal point on the lifter for valve speed without the lifter gouging. But when it comes down to it most of us are just concerned with what we can easily buy. So i used to do a lot of mental builds and i felt that a solid lifter flat tappet cam, perhaps with a small base circle with high ratio rockers and a large 30 degree seated intake valve could be a real street sleeper. Pontiac super duty engines used a 2.100 intake valve with a 30 degree seat and some guys like to put them in d port heads to extra valve spring height. This valve has much more area than the port which means that its "curtain area" as some people call it would match the port area at a lift somewhere below 25% the valve diameter so high lifts probably arent needed as the port will choke the valve. Well allegedly a ford 1.72 rocker arm is the right length for a pontiac cylinder head. So a pontiac build is one option, maybe a 350 or 389 but i think most pontiac heads with any compression are small for my liking on something bigger than a 400. Another option would be to use a pontiac valve in a chevy or ford or chrysler with a small exhaust valve to make room and use a dual patter camshaft to het the exhaust out. The 30 degree seat and the fast valve acceleration would allow significant flow with low amounts of advertised duration, high ratio rockers on the ford and larger lifters would allow some lift but not a lot would be needed as the port may choke early. An engine like this could have a smooth idle because of low advertised duration and and valve lash but still move more air than other engines with similar or larger camshafts. And as david points out the cam can save you money to be spent on some other part, perhaps a crank to get more torque or perhaps some fancy high ratio rockers and light weight retainers if you find valve lift important. You may note that comp sells cams like this. They make a series of circle track cams with 106 or so lsa usually. they are solid lifter flat tappet and a little less aggressive as they are to be used with 1.7-1.8:1 rocker arms and they sell them as "max area" cams. You may also notice that pontiac having short valve springs has been building big valve small port low lift with a 30degree seat angle setups since the beginning. Perhaps the super duty 389 was more clever than we all thought?

[@luckyPiston]

And after all that your point is what ? or we should run a goat motor ?

[@danieldimitri6133]

I guess thats there's not only one way.

[@buddoctor1]

Very good advise on lifter bore would be great to see a how to check lifter bore and how to correct if needing and prep for assemble

[@tonyschiffiler4816]

Thats what I call crunching numbers to gain power , thank you very much.

[@Spudderr]

Just like to take a minute and thank you for all the information you’ve given and continue to give

[@garygrimm1704]

Great tech and info on the flat tappet cams. Wow! Thank u David for teaching and sharing.

[@bcbloc02]

I build engines that run in classes that are rpm limited to 2600 or 3000rpm. The 1.5" flat tappet engines that I have built for people are always front runners and several are multi time points champions. Even on engines that run 5000-6000rpm I can get a broader flatter power curve with the flat tappets than the rollers. Peak hp numbers will be pretty much the same but the flats do require more attention to keep from wearing out when you start getting the spring rates up to run more rpm. For an engine that mostly will be used at 4K and below I think an agressive flat with big lifters will make more area under the power curve most every time.

[@DavidVizard]

Bcbloc02 - Tell me more - this sounds very interesting!! DV

[@bcbloc02]

@@DavidVizard I often use a 252@.006" that has 154@.200" that smokes anything roller for the .200" number with that short of a duration which is critical for making big torque at very low rpm's.

[@roadrunner4404]

I thought you were about to tell us about mushroom tapper came. Great info Sir. Your lifes works are appreciated.

[@peggyparrow2059]

I really enjoy your wisdom , learned alot from your books years ago!

[@jimmywaters3987]

David, Excellent video ! I have most of your books. In this video, you didn’t mention using lightweight toolsteel lifters on a nitrided cast cam core . Looking forward to hearing your take on that. I know for a fact that Nascar engine builders used lightweight toolsteel lifters on hardened steel cam cores. The lifters were DLC coated. Thanks !

[@bigdogsportingtonyb2833]

True experience. Thank you very much for your videos and knowledge. Greatly appreciated.

[@henrysmith8012]

I have been running an Isky flat tappet cam on the street for years in a 355 small block with a Procharger with no problems.

[@robertmiere5348]

Another great video, as am going for the Howards 289 Le Mans Cam for my 289 Cobra engine, I didn’t notice the music until I saw the other comments would prefer no music, many thanks David.

[@GnarshredProductions]

I worry more about the reliability of flat tappet cams than I do about the performance of them especially on a high performance engine where you have to use stronger valve springs to avoid valve float at high rpm's. Having a cam lobe go flat after putting all the time and money into building a nice engine for your hot rod seems like it would be a soul crushing experience.

[@geoffmooregm]

I agree. Plus the shaved off metal can do other damage. I *Think* the flat lobe problem has been solved by the good cam companies. I am running a mild COMP cam in my little chevy V6. It is just a street/off road engine. I run Redline oil because both Redline and COMP told me it has plenty of ZDDP to make the cam last as long as the engine. But COMP said it is not necessary to have a high level of ZDDP due to the mild spring pressure. But since I don't put a ton of miles on my engine I just change the oil annually and it has worked welf for over a decade so oil price is not a concern.

[@427_FE]

@@geoffmooregm I have never had a cam go bad in the 40+ years I have been in the business. The key is proper break in. Making sure engine starts right away, using the manufacturer's assembly lube, a good grade mineral oil with proper additive, and running at manufacturer's specified time and RPM. In the near future I will be tryng David's Oil Extreme on a solid tappet cam for my 351W.

[@DodgyBrothersEngineering]

@@427_FE agree Jeff, never lost a cam lobe with proper break in.

[@cecilandrews1875]

@@geoffmooregm I've seen more flat lobes and Cupped lifters. If flat tappet cams and lifters were so good the rollers would not be installed an engine because of cost. What the roller makes more RPMs last longer, I've yet to see my first bad one

[@AmericanThunder]

In a high performance engine, you'd use solid flat tappets, and being lighter, they don't require as heavy a valve spring as hydraulic lifters would for a given profile size, plus the solid lifters can't pump up at extreme rpms.(I shift mine at 8500) You could run solid rollers for max effort, but for a performance track/street combo car, those aren't the best choice for such duty. Solid flat tappets are reliable, and produce good power, with virtually no rpm restriction.

[@robertclymer6948]

Hi All. I am a relative newbie to all this cam and valve train info. Makes my head spin. I will have to study a lot more before I decide on my cam and valve train setup for my 460 BBF engine. Appreciate all the knowledge shared here in the comment. Cheers and blessings to all from Motown.

[@williepelzer384]

All you need to know is DON'T BUILD A 460.

[@joesmith306]

I use a higher rocker ratio with a flat tappet cam to make up for the smaller duration.

[@MrXerxes415]

Once more you are head and shoulders above the competition. You have given huge huge benefit of saving dollars while achieving high power levels while easily making it last. Not one person on KZbin is taking your counter intuitive stance on hydraulics beating rollers and coming up with 500 tq motors.

[@weofnjieofing]

Flat tappet engines sure sound best at idle!

[@paullutherborrow637]

I love watching stuff like this The 100% reason I’m moving to a roller camshaft is because Holden V8’s have problems with wiping loans off ( as are a lot of engines with the quality of lifters available over the last 3-5 years )

[@luckyPiston]

Did ever consider a lifter bore grooving tool ?

[@paullutherborrow637]

@@luckyPiston no Holden’s have plenty of oil to the lifters imho

[@doctorromex7804]

Great content as always, I look forward to more to come. THANK YOU

[@mback12000]

The content and subject is excellent. I agree with the others, the music cheapens the video.

[@marvingvx1]

Michael - I am working on a video now and turning down music volume, Let's see how that works out!

[@michaelvoigt724]

Love your videos, you're very experienced and it shows!

[@juiced71]

Some really great info ! My old neighbor talked me out of a roller cam for what I was doing it made sense not to spend all that money he said just go with a solid cam the poor mans roller lol

[@capriracer351]

One of the keys to making a flat tappet cam last is a round, straight lifter bore with the proper clearance that is in the correct location. If the lifter does not rotate as it should, the failure will be very quick. With all the good points you make here, I started to think back to the old mushroom tappets. That took the acceleration rate advantages you spoke of with a flat tappet cam to the max. What has your experience been experimenting with that configuration? Might be an interesting sub topic for part 2.

[@johnhennery8820]

Another great video thanks again for your time very good information I built a 289 back in 1990 and I was going to college at the time to be a machinist and I had free use of all the equipment I needed so I learned how to bore line bore perilel the block also how to grind the rods and put a 125 finish on them thay were,43_40 steel wen I was all done it was balanced and I used a large 68 damper with the balanced forged pistons and reablanced them the engine was so smooth and it was really fast I still have it and now seeing your videos on cams and head porting I'm going to build my 67 4 barell heads and this time I'm going to put it on a Dyno and see what I have thanks again for your help

[@Lifeistooshort67]

How is it going with your rebuild. Would love to see those numbers. Keep me posted if you can.

[@hackitgarage6503]

I watch this to learn I often find myself thinking I hope I can remember all of this

[@rogermunoz8134]

Much respect & thank you for sharing your great knowledge! Well explained”

[@Pereke69]

Wow im a huge fan of yours since a lot of years ago, i have all your books, but dindt know where doing a video series!

[@inabrungart2470]

Thanks for the info Dave.

[@joedobbins870]

I think David Visard is full of it!

[@stevenbongiorno9277]

David, what are your thoughts on the Rhoads lifters? I’ve used them before, and noticed a little more torque before 3500 rpm, on my street car. I’ve installed them again in my latest top end rebuild. I had lost a lifter, and lobe on my last Comp Cams that I had used. I did some investigating and found out that a lot of people were having the same problems that the newer motor oils are presenting with flat tappet cams. The Rhoads worked well before on an engine that I drove a hell of a lot more than my last engine. My car is basically a show car that I’ve put a lot into looking for more power out of. I only put a couple of hundred miles a year on it. So you can imagine how shocked I was to find the damage to the cam, after I was using Mobile One. I changed it every year, before I drove it. Now I use the Valvoline VR1, and a small dose of the Lucas Zinc Plus, cause I don’t wanna go through that again. Back to the subject at mind. What are your thoughts on the Rhoads lifters? I hope you see this question, and can answer it. Thanks in advance

[@davidcolegrove8818]

Excellent video!

[@jessesyfie7244]

Excellent very indeed. I was rite a flat tappet actually makes more power than a roller using very short duration cams.

[@barrykilts4506]

I have several of D.V.’s books along with others.I don’t have the budget that many others have and mine are for my amusement so I go for bang for buck along with durability and more often than not I’m happy and don’t mind relying on other peoples info who have bigger budgets and longevity and reputation in the field

[@sideswiped6874]

thank you for the video. can you give us more info and your thoughts on "High Ratio Rocker Cams",,, please???

[@rotaxtwin]

Long live the flat tappet! I can't afford hydraulic roller valvetrain. Thanks DV!

[@marvingvx1]

Mr. rotaxtwin - The advice to make a flat live is not over yet!!!

[@rotaxtwin]

@@marvingvx1 That's good to hear. I will be watching.

[@RobertsChannell]

I suppose a benefit not mentioned with the roller is the possibility of a wider power band with the 50 mark being shorter and the 200 point being wider , so less off cam reversion . The extra lift helping compensate for the shorter 50 as well . a dyno curve of the two cams would be good to see if that's a true visualisation .

[@alonzahanks1182]

I could see that but 336 lift is a stock chevy lift with race car duration at 268 it was probably 460 or 480 lift and thats more like imcsa roundy round size Chevy roundy round box engine . I actually did that with 355 Target engine with B&M 144 Blower crane anti pump up lifters but you need 400 pound springs to not float valves and roller rockers . I thought you were going to say 560 lift 220-240 lift that would lever on cam lobe and open valve realy fast Thats like old tech But did pretty good too. Sounds like olds Hurst early Tech olds built tough engines in Delta 88s their 350 we angle cut heads on.

[@purestress2597]

that would make sense seeing as too my knowledge roller cams were made more for smooth running rather than power

[@bw6538]

Great information I just hate running rollers on the street they were out to quickly always wondered if flat tapped would be close in the same power range and love the sound of solid cams

[@urcarsucks6959]

are you buying cheap lifters? I've never had issues running them on the street. There were all sorts of factory roller cam SBC's and all LS engines are rollers...never heard of lifter failure being a big concern. Except for AFM/DOD applications, but that's a different topic

[@johnsheetz6639]

460 ford's has huge lifters. I've seen some wacky you wouldn't want to put on anything else cam profiles. On a flat tappet big block.

[@ProjectFairmont]

I have built a numerous 5.0 based roller cam SBF. One I am doing now for a mild application, is a used split duration Explorer 5.0 cam (F4TE-6250-BA) 256/266, 0.422/0.448, 116 with new Ford roller lifters, lifter cage and keepers. $250 total for these. I otherwise agree with your cost analysis.

[@DavidVizard]

Ford are notoriasley bad at getting the LCA for almost all Windsor style motors. If you want to use a stock cam get the one from - I think, the Crown Vic that is on a 107 LCA. That will be worth about 20 hp and 20 lbs-ft minimum.

[@ProjectFairmont]

@@DavidVizard to my knowledge the CV 302 was only offered as flat tappet before being replace by the 4.6 2V. The OEM 302 HO cam is 115. There are some inexpensive re-ground rollers that I can look at for a better LSA.

[@ronstanleyhunt1135]

Great on the old motors ,,,,,how about ,LS MOTORS. ANYWAY I LOVE OLD MOTORS. THANKS ,,,GREAT JOB DAVID ,,,I LOVE YOUR WORK ,!!

[@HotRodDave]

I enjoyed the video. I am always trying to learn more.

[@skylinefever]

This is interesting, but I have heard many stories of low quality flat hydraulic lifters not lasting long. This is even in situations where people use special high ZDDP oil. Some people buy roller hydraulic lifters only to avoid that situation. 4:28 This would explain why the 350 truck engine used hydraulic flat lifters until 1995, whereas the Camaro, Corvette, and Firebird got hydraulic rollers in 1987.

[@bartpang]

Another factor is the valve springs generally cost less.

[@johndunn678]

Dont forget to add in the cost of having the internal clearances checked & possible machining that may be needed for a 383 SBC. Not everyone knows how to clearance one and to check the cam and the block.

[@marvingvx1]

--- and therein lies the subject of a 15 min video - thanks DV

[@luckyPiston]

The video is for everyone, the actualization of 82 ft pounds of torque is there for those who are willing to get their hands dirty, it's a basic puzzle not a rocket to the moon.

[@barbar9919]

Thank you David for your videos.

[@thisisyourcaptainspeaking2259]

I agree with Mr. Vizard.

[@peggyparrow2059]

Comp. Has lifters for hyd. Cams with a .012 oil hole in the bottom and Howards had a .022 hole.

[@walterabbott5910]

David Visard on roller rocker arms

[@donwalsh7521]

Thank you Sir once again!

[@groomlake51]

@13:33 peak power RPM on the flat tappet says your crazy😂I kid I kid

[@craigchiddo2794]

Hey Mr Vizard did you have your surgery if so get well quick there's plenty of airflow waiting for you to find

[@crawford323]

I think I could better understand with illustrations. All this begs the question, what flat tappet cam's data and performance would match a roller cams performance for what application?

[@MX-fo2nu]

Great experience Shared, thanks a lot

[@danielwilson6665]

Thanks for another significant report on a essential topic for important builds. I’m using bronze lifter bore bushings in a 351” Cleveland 4-bolt main (D2AE-CA) block to provide an extra measure of oil control at the lifters, which typically flow excessively in production blocks. The solid roller cam and lifters is a NOS set from Reed Cams. Do bushed lifter bores provide any significant performance or parts longevity increases over the stock iron bores ? The bushings and/or screw-in oil passage restrictors work well to correct the marginal oil flow to the main bearings which is a common Cleveland engine problem at frequent or sustained rpms above 6000.

[@johnjaniak473]

I did the lifter bore bushings in my Cleveland, from what I understand, when the lifters are moving up and down at higher rpms , it can cause aeration of the oil, which ain’t good of course, the remote line was a band aid for that problem , I also did the Tim Myers cam bearings instead of screw in restrictors , best of luck

[@danielwilson6665]

@@johnjaniak473 , good call on the Tim Meyers grooved Cleveland cam bearings. Tim has quite a selection of Cleveland specific components available and he is a good guy to do business with. I agree with the questionable benefits of using the external oil line on a Cleveland.

[@bobqzzi]

Love these videos. Could do without background music- I'm betting a lot of people watching this have poor hearing from being around engines for years

[@kristjanstefansson2765]

Great video as expected sir. Reminds me of a chapter in one of your book were you address these things as well. Great to see this still holds true many years later ! However it seems to me you got the hp and torque mixed up in the listing where you compare the roller vs flat tappet 355. Looking forward for part 2 Best regards from Iceland 🇮🇸 Kristjan

[@racerd9669]

Just check out the 2011 Engine Masters challenge and you will see a LS engine that placed 2nd with a .904 Dia flat tappet. It was the only engine in the contest with a flat tappet cam. What David failed to talk about is lifter dia. and how much faster you can open the valve with larger lifters.

[@luckyPiston]

He's building a small block here ! so how much to bore out the lifter bores ? isn't he talking about working with what you have or did i miss something ?

[@racerd9669]

@@luckyPiston Yes he is I agree, but he never addressed how much better a flat tappet cam can be when you have a larger Dia.

[@jesusisreal3209]

@3:30

[@havoc9926]

great video.david vizards the man.keep the content coming.

[@mikemcnamara2943]

David, Most of the videos are great, but you need more visual aid, use the white board and draw cam profiles and LSA and so on. You hooked me on the first video actually porting the head. Can you make a video w/Pontiac heads RA3, or RA4?

[@chetmarcotti1124]

Thank you Mr. Vizard, that came to explain some thing that have been bouncing around in my head for years about solid lifters. I had a1964 1/2 and I put a solid lifter cam in. But I was pointed to use a flat tapper from a 427 lifter of that days engines. The engine ran exceptionally well for a stock 289. These lifters had a solid zone on the top and the bottom. But the center zone was cast (I believe) that was actually a spiral with about 4 to 5 spiral webs. Which from your description sounds like it would force the lifter to spin. Any thoughts?

[@johnparrish9215]

Sir, the background music is making it difficult to understand everything you're saying, please lose the music.

[@dillonoliver27]

Or atleast lower it. He kinda has a monotone voice so having a background noise could help someone with adhd.

[@jamesmedina2062]

me thinks you just love music too much and you wish it was better eh?

[@joedozier3422]

Awesome video and thank you Sir

[@jimstewart8394]

great info , but the music is annoying , i will still watch thanks.

[@marvingvx1]

Jim, Thanks for your comment, Others have voiced the same thought so we are going to cut the background music volume and it's overall use. Let us know how we do. Thanks DV

[@richardmoerke9329]

I know dodge had motor with mushroom lifter so to your point David this would make a big difference. Can you still get them? And again you’re the man!!!

[@luckyPiston]

Mushroom lifters take up more space inside the engine, can you even fit them in a small block, or even a big block for that matter ?

[@KompressorPete]

Dear Mr Vizard. With your experience, knowledge and fire in the heart I think it would be very interesting to hear about your personal favourites during the decades. For example: 60’s, 70’s, 80’s and so on, best engine for Street/race, best in US, Europe, Asia etc., best cylinder head, configuration (V, inline, boxer etc.), best for the buck (amateurs such as my self), your favourite engine Sound, - and lastly how would a Vizard engine look like if you started on a blank peace of paper. Br - Peter Lundorf - Denmark Europe

[@marvingvx1]

Peter - I will put that in my research list for a possible subject ----

[@nadjisutherland8058]

David, excellent presentation with one exception. The background music noise is distracting to the extent it prevents me from comprehending your message. Maybe due to my age, over 60 now but still a large % of your audience. Still listening by tho. Tx for your effort, john

[@pmd7771969]

A low buck high hp motor can be built now a days with a truck block and a diesel set of turbos.

[@jamest.5001]

I recently tried liqui-moli additive, in a motorcycle engine, it seems to have a decent amount of friction in the cam followers/rockers, a roller would seem much better, it's a old engine design, overhead cam, from the 70's Honda, I haven't used it long enough to say if it's good or not, but it is slick, basically a graphite grey color, so the oil will be black even new! I'm hoping it will reduce friction, and produce more power, I'm going to checkout your suggestion!

[@RUBIZEN]

Does the transmission/clutch share the same oil? Does your clutch feel the same? I'm wondering how the additive will affect clutch frictions and steels.

[@skylinefever]

@@RUBIZEN Good point. I have heard that MOS2 is terrible for wet clutch function. Motorcycle specific oils are typically formulated with zero MOS2.

[@robertellison4691]

Do hydraulic lifter and solid lifter camshafts have the same amount of taper ground into them? Do hydraulic and solid lifter faces have the same amount of radius as one another? Do GM, Ford and Chrysler engines from the 1960's and 1970's all have the same amount of taper and the same radiuses?

[@MoparMan-ff8fb]

so does BG oil additive RF7. I run this and ROTELLA 15w40 in my slant6 and 318 during the summer months and during the winter I back off on some of the ROTELLA to help with cold cranking . I'm going to be building a 1978 mopar 360 for my 65 dodge dart what do you recommend on a buget . I'm going to be running a Hughes cam racing 998 automatic with 2800- 3000 converter and a 8-3/4 rear with 3:55 gears

[@luckyPiston]

Wouldn't u b better starting with a 360 magnum or at least magnum heads ? building a 78 would b equal to building a chevy 350 with open chamber smog heads when Vortecs would be a far smarter move !

[@MoparMan-ff8fb]

@@luckyPiston I've already got money invested in heads and block air gap intake ect. the heads are J heads with 2.02 valves I will be porting and after market pistions with shorty headers ect

[@joe-hp4nk]

Will higher ratio rockers help in a low duration flat tappet cam? Adding lift with the rockers instead of the cam would makeup for the short duration.

[@Dave.S.TT600]

thanks for the videos

[@pmd7771969]

When dyno ing, many fo4ce induction engines the cam choices didn't make as big a difference power wise as you may think. Bloodviking

[@427_FE]

why have mushroom tappets fallen out of favor ? They where the thing to have, If you couldn't afford a roller, back in my machine shop days. Isky made the spot face tool for clearance, I recall.

[@BubbaAyers1969]

I was waiting on Jason to appear

[@chestrockwell8328]

Camppppp Killlll is that what you were hearing in an a soft echo?

[@jerrygregory5959]

I want to covert the GM hyd flat tappet lifters part number 12371044 to solid. Can this be done? These lifters seem to be the only flat tappet lifters that are not failing for our shop. They have the fused on hardened foot. We have tried all others and they fail.

[@regdor8187]

The price comparison does not include the wipe out of the flat tappet lifter as is becoming common......

[@MrRoughNutz]

i love this

[@HWPcville]

I need 8 tappets for a 30 yo diesel engine (Westerbeke) but none can be found. Are there businesses that could/would make them for a relatively reasonable cost? Can tappets be reconditioned?

[@nadronnocojr]

Thank you sir

[@turbo32coupe]

please make the voice stereo.

[@Cliff_Anderson]

Because I've read your books, I understand where you're coming from here. I think a graphic showing the area under the curve for the two types of followers would be instructional here for those who aren't sure what you're talking about. The roller cam is basically limited by the thrust angle of the cam/roller interface, whereas the flat tappet is limited by the diameter of the lifter. I'd like to see a graphic where the two are at the bleeding edge and how the curtain area is affected in the first couple hundredths of lift. Or a "race to .25D"

[@DavidVizard]

Clif, Are you the 'Cliff' I know from old??? Your comments are spot on but there is a limit to what can be comfortably stuffed into 20 mins. DV

[@Cliff_Anderson]

@@DavidVizard Haha! I wish I could claim to have met you, but sadly, our paths have never crossed. It's only as an older man that I've had the time and resources to put all the things I've learned from you and others into practice as a hobbyist. If folks who get most of their information from videos only realized how much depth they are missing by not reading!

[@hondatech5000]

Thanks again.

[@timbo19751975]

Guys, please sort your audio LR balance and auto gain out.

[@dondagy9109]

Why was a 6 in rod used in the graph? I noticed you didnt mention it, and you said stock, and 355, yet isnt stock 5.7? Was it just a misprint, or was there actually 6" rods with offset pistons, compared to actual stock at 5.7" for the 355 combination?

[@totensiebush]

I'm surprised that the stroker crank gets you about 25% more torque out of 8% more displacement

[@barrykilts4506]

David how much of oil extreme is required to break in a flat tappet cam

[@jeffrykopis5468]

Mr. Vizard, why did the large port, canted valve engines (Cleveland; 429/460; BBC) all get 1.70 to 1.73 stock rockers, while small port, inline valve engines (SBF, SBC, SBM, BBM) engines had to make do with 1.5s? Is there any reason to NOT install 1.6, 1.65, or 1.7s on the latter, besides piston to valve clearance?

[@dantheman1998]

Pushrod diameter? I know you need stiffer pushrods the higher the rocker ration goes. But that would be my guess that the BBC stuff got a thicker pushrod diameter to handle the higher rocker ratios.

[@thekingofktownsixni]

I have a flat tap around 512 lift in a 355 with 1.5 roller rockers.i would like to make big torque and good horsepower how can I get to that place?

[@cbobscountrybunker2312]

Grate video , i appreciate any and all of your information. Would it be worth running a mushroom lifter on a solid cam?

[@luckyPiston]

Why bring up a solid when most people are to lazy to run one let along set it up properly in the first place ?

[@cbobscountrybunker2312]

@@luckyPiston it doesn't bother me to set to lash. i have some y block fords around, and remembered that you could get a mushroom lifter for a sbc at one time. I thought they might have some untapped advantages.

[@joesmith306]

Can you still get mushroom lifters, thanks.

[@ianshaw8273]

What do you think of an mushroom style lifter

[@Thirdgen83]

Oil Extreme contains chlorine which is corosive (not good for engine parts).