Ask Roger: When building up a stock v8 motor how important is lift and duration in the cam?

It's ASK ROGER time! We just uploaded the latest ASK ROGER video and are pumped to announce our December WINNER! Congratulations to Michael Kerschner on being selected as the ‪#‎AskRoger‬ questions of the month and winning a set of E3 Spark Plugs (up to a V8)!
Michael Kerschner asked "When trying to build up a stock v8 motor how important is lift and duration in the cam that u pick to put in it?"

[@McFly-guitars-n-stuff]

When I was a kid growing up in the 70s guys would put an incredibly crazy cam into a mostly stock engine. The result was it had a really cool idle. But the reality was the car was slower than stock LOL. Not to mention breaking rocker arms and bending pushrods at higher RPMs. Just a little bit more than stock and a few tweaks like headers, Aluminum Intake, modest 4 barrel Etc can make a motor come to life on a budget. A guy I used to be friends with really dug Mopars. He used to take at 318 and put a 340 cam in it, Aluminum Intake, four barrel, sometimes headers, and that would really perk up a 318. He did have one Volare or an aspen I can't remember with a 318 with a pretty lumpy cam and it was pretty gutless. But I think he bought it that way. It makes sense if you're going to do a build copy a successful build you read about in a magazine or online then you won't waste time and money.

[@tonymunn]

Thank you. I learned enough to know, I don't know anything.

[@codemang87]

This totally brought me back to high-school autoshop. Thanks for the great explanations!

[@mikeraftis6332]

Stock engine put a 205/215 for towing. Stock with mild performance 218/225. Stock with increased compression 224/236. Lobe seperation 108 or 110. ICL should be advanced to increase cylinder pressure in low compression. 218/224 LC 110 installed on 106 is good for most applications.

[@craigpierce7996]

Now take that same high lobe separation, add some lift and duration, put a blower on it at 15psi, and you have a rocket ship! High lobe separation at boost stops blow-thru, at the expense of higher EGT's. Love this explanation you make. Hope people are paying attention!

[@Scubasteve22]

A good video roger. Just a general note that a tighter lsa will usually perform better everywhere over a wider one. Sometimes when I want to kill a little bit of the low end and focus more on top end, say a large ci engine or one with a long stroke, I will widen it out a little or adjust the exhaust valve opening point.

[@WesternReloader]

Depends on the head flow, exhaust, desired rpm range, weight, usage, tire size, gearing, trans, etc

[@chopperking007]

All us rev heads have made the mistake of too bigger cam for the street and then gone back to a milder one

[@jakewade7388]

Straight out the book

[@Moparmaga-1]

Could you please explain how important the Overlap is & give examples of street car & bracket cars. Also how a cam with the right amount will either build up your cylinder pressure for low end power of have to many degrees and not build it till further into the rpm range which would definitely be a poor choice for a street driver. Thanks. I just found out the math which is simple, mine adds up to 82° of overlap. It has 239 in & 246 ex duration! with 484 lift in & 484 ex. 108 lsa the grind is comp nostalgia 21-671-4.

[@bluedemon79]

If you need a cam, call the cam company of your choice and they will pick one out for you based on the engine and car information you provide them.

[@ThunderAppeal]

This is ground breaking information.

[@chrisbreckenfelder7227]

Or one they got off the shelf...either or....lol

[@terrysibley9636]

Very good. Thank you. Happy memorial day everybody

[@ramazanevrensel6535]

Hello , Can you suggest a formula or method that you use when calculating cam shaft lift values? Thanks

[@ronsmith7739]

Valve over lap is extremely important one needs to know this !!!!!!!!!

[@bighoss8531]

Yup. Scavenging is important especially with weak flowing heads.

[@ashensilva5559]

plz explan how to calculate LSA in single and dual over head cam

[@jerzzzeyful]

Wow.. after 3 minutes of listening to this made me dizzy.. after 5 minutes I dont remember a damn thing he said.. Great video

[@morrisw7227]

Did he ever answer dthe question?

[@markbogle8062]

Does lobe center line angle depend on the valve to piston size?

[@bryantracing3022]

Do u have to use zink oil on new bearings

[@Moparmaga-1]

What's the formula (if any) For duration vs cubic inch. I'm building my 1st big block stroker 471 cubic inch mopar from a 400 block. I did buy a cam it's 260 264 duration@.050 with .616-.620 lift. 108 lsa, I am hoping it's big enough to bleed off some of my 11.3:1 compression so I can run pump gas, I have alot of aluminum parts & a big radiator. This car is intended to be a fun street strip car.

[@petenielsen3813]

Got 2018 5.3L chev pick up want more power for pulling low end tork what cam would work well bone stock 67000 miles would I have to replace lifters too

[@jamespepper2541]

I have a 327 small journal 30 over and, I want to use Lt1 heads set to work on my engine and ported and polished with the Lt1 cam!!!! 😎

[@homadu1830]

But what if your rpm is very low does the affected

[@grndragon2443]

So in other words, if I want to have more power in the usable range (600-4000 r.m.p.). I will need a lot of lift with short duration?

[@johndaroza2987]

Yes true. But you need to get everything right not just the cam.

[@brianfrancis2862]

im building a fe 390 im wanting this cam for my street car it 1965 galaxie want to use stock heads an train it has c6 tran want sold lifter what cam should i buy

[@rogersome1413]

Even 7 years ago increasing overlap increases cylinder pressure

[@jermainejenkins4997]

I have a 96 Chevy Silverado with a 5.7 vortex and I'm looking to make more power with a thumper cam with headers so what is your input on this for me I need help

[@gregblau8082]

With a 107 lsa I really doubt there's a way to make that cam work with your computer. Look at listings on summit's website. They all say if it works with fuel injection. Maybe check out the lt4 hotcam. You can get them pretty cheap too. If you have a carb or aftermarket fuel injection it will work but probably not the best choice for power. Do q Google search on vortec lift. I used comp 981 springs, tapped down the valve seals and did the ghetto grind.

[@DavidLee-no9uc]

I'm want to put a Big Lift Big Duration hydolic cam in my 440. I want the engine to come alive around 2500 to 3000 and peak at 6000. Any suggestions? I'm leaning towards a Summit Racing products brand cam. And how important is Degreeing the cam? I will be using Gear Drive. Thanks

[@Scubasteve22]

howards cam flat tappet 7212012-08. Howards is one of a few with a landi's cnc grinder. You should ck it with a degree wheel, but if you didn't these come out perfect every time.

[@jamesford2942]

Big lift and duration cams move the power up in the RPM range. If you want it to have power at lower RPM like 2500 then you don't want to go too radical. If it's a driver, realize that most of the time you are at 3000 and below.

[@outtowin75]

This video didn't come close to answering the question... Just read some basic definitions....

[@TheSol115]

bujias para duratec 2.0 ??

[@thedobermangang3503]

I GOT A 1990 K5 BLAZER 5.7 WITH ECU GOT ENGINE REBUILD GOT THE BLOCK BORED 30 OVER AND DID A FEW UP GRADES IM USING EX262H CAM IN IT WHAT WOULD BE A GOOD COVERTER TO USE I TOOK THE STOCK ONE OUT..AND GOT 2000 TO 2400 STALL .. IS THAT GOOD WITH THAT CAM

[@pjnelson5827]

If you still have the stock TBI heads, one of the best things you could do is to get a set of 1996 or later Vortec heads. They would work with that cam much better. If you go to Vortec, you'll need a new intake manifold. That cam is mild enough that you could get by with your stock converter. If you are going to swap the converter, keep it low.

[@longtat6587]

Does anyone know how to calculate the camshaft?

[@baby-sharkgto4902]

I might. Explain?

[@miholju]

This video is just the tip of the iceberg with respect to cam profile design (calculated 5th order, 10 boundary conditioned B-Spline curves to generate cam lift profiles that conform to specified open and closed timing events).

[@eveliomolina4186]

does the cam shaft on 305 fits 350??

[@oldfatandtired6406]

It will fit. But why?

[@DANTHETUBEMAN]

its not, i had my cam round ground, smoothest engine you ever seen 😊

[@tttony9426]

thanx for the illistrations,us guys are mostly visual,,example i only read the funnies in a playboy maginzine,😉

[@regdor8187]

Sh*t, I thought you were going to explain Just what those different angles really do to the torque and peak power band... Anybody can read the literature about the mechanics of it, I guess we need some one with actual understanding to paint a picture of how the information can be used....