350 CHEVY Dyno testing ProMaxx heads and Summit 1202 4/7 Swap Camshaft! CHEAP EASY 415HP!

[@yarrdayarrdayarrda]

2:28 The LS firing order is both a 4/7 and 2/3 swap from the standard Chev F/0.

[@JoshuaABartlett]

I was going to state this as well

[@hollowell427]

yup

[@goldsgarage8236]

You are correct Yarrda. Yes, i should have mentioned this. Here is a question, why do you think Summit did not include the 2/3 swap as well? AG

[@JoshuaABartlett]

@@goldsgarage8236 summit does offer an LS firing order for SBC cams. It's builders choice on whether or not they want a full ls firing order or something in between. I would ask you why gm swapped 4/7 and 2/3 on the LS.

[@TimothyArnott-m7z]

Hey AG, Tim here, SUPER cool test.. the cam isn't to lumpy, ergo the E-Brock did good.....go to a lumpy cam, the E-brock will be kantanerous at best, its idle circuit leaves MUCH to be desired.....the Holley Brawler wud be my choice I've had this b4......lumpy cam, go with the Holley....no overlap, E-carb wud be fine. . fun, intresting tests.... I enjoyed... TY sir!!

[@goldsgarage8236]

i always enjoy your comments Tim.AG

[@DanielStahler-m8f]

Holley all around,is just a better carb

[@TimothyArnott-m7z]

@DanielStahler-m8f i have to say i agree.......but AG has to go with customers sometimes.....maybe this time his customer isn't married to the E-brock........but serious cams, need a Holley........daily driver, no lumpy cam, the E-brock is quite responsive.......get into lope, the Holley is a no-brainer.....enjoyed the comment sir!!

[@billlittle4285]

Hi guys, finally able to watch a video, good job Alan, Darrell, and Austin, and also Mike who edits the videos!!

[@goldsgarage8236]

Great comment from an expert, thanks Bill.AG

[@DarrellWatters]

Thanks Bill, that’s a great compliment from the “professor” it would be awesome to involve you in some of Allan’s videos to help tune and give your final thoughts on the dyno day!!

[@JW-hm6ou]

Nice to see that you look at the comments.

[@goldsgarage8236]

For sure, thanks Joel. I look at them all and learn from doing that. AG

[@nerradnosnhoj5122]

Thank you for the video All of those carbs worked very nice , Quadrajets are a little tricky but when sorted ,are close to being equal to anything out there, Austins is dialed pretty good for sure ... This is certainly a very healthy 350 , I run a Quadrajet and use an adapter to a square flange dual plane intake , mine adds around 1/2" height.. it works very good ...

[@goldsgarage8236]

Thanks for your affirmation Nerrad. AG

[@DarrellWatters]

Bill Little is one of 3 best Q Jet tuners around and Austin has been tutored by Bill and learned things on his own as well, so we couldn’t ask for a better expert on those carbs!!

[@billfioretti3013]

Thank you. Good build, Alan. Good results. Will go fine in a nice streetcar. Informative and enjoyable conversation post- dyno runs.

[@goldsgarage8236]

As always, thanks for commenting Bill.AG

[@doctorwhodj]

The results ive been waiting for on that Sum-1202 cam

[@goldsgarage8236]

Thanks Al, hope you found it helpful.AG

[@robertwest3093]

I’ve noticed one important thing that the beginner engine builder sometimes doesn’t pay attention to and that is piston to deck measurement. Unless you pick a performance piston that you verify the compression height, most rebuilder pistons have an extra .020 or so removed from the top of the piston. I’ve seen some piston to deck clearances as much as nearly .060!! That’s easily a point of compression lost!

[@goldsgarage8236]

Thanks for the info Robert. We always check deck height and use it to calculate CR and Quench. AG

[@newcitycarpet3675]

Wix has a race air cleaner for drag use. It's impressive with its claimed flow rating with its low restriction design. I pickd up 1 mph to 103.87 in a stock 1965 GTO. Every bit counts! Thank you for the video.

[@goldsgarage8236]

Thanks for the real world experience info NCC. AG

[@robertwest3093]

Another thing, those ProMaxx cylinder heads are one of the best power per dollar heads out there.

[@goldsgarage8236]

I agree Robert, this is the second set we have used and we will use them again.AG

[@captainrawn]

This was a really nice street engine build Alan. The results are excellent for that camshaft. Can you please post a close up of the dyno results along with a graph that we can freeze for easier viewing on this and/or on future builds. Thanks!

[@goldsgarage8236]

Thanks Captian. For sure, we will try to do better. We were short of resource on this one and lots to do with the carb and air filter tests. AG

[@wrenchboy322]

Another fantastic video. It was great to see how the carbs performed, very interesting with the Q jet.

[@goldsgarage8236]

Thanks for watching and commenting Glenn.AG

[@robertwest3093]

I couldn’t help but chuckle when you said the engine made 326 HP on the front two barrels only 😅 That’s actually pretty impressive considering very few small blocks made that much or more from the factory!

[@goldsgarage8236]

Good point Robert, but can you imagine how I felt when Darrell pulled up the results of that pull on the screen, before we knew what happened. AG

[@DarrellWatters]

Ya Allan said if it doesn’t make any more power than that he was taking it home lol, glad we found the problem 👍🏻

[@pontiac411]

Would have been interesting to see the graphs laid over each other to see the curve as well as what the averages are.

[@goldsgarage8236]

Thanks for your comments Pontiac. Yes, we could have done a better job of showing the results. We were a little pressed for time and resources this time, trying to get a lot done. We will work on getting better.AG

[@lawrencemallais1884]

FROM MOTOR CITY, GREAT VIDEOS KEEPEM COMIN !!

[@goldsgarage8236]

Thanks Lawrence, Love the motor city, I lived there for a 6 months working for US Steel on Zug Island.AG

[@pockets5628]

That Summit SUM-1202 is a nice street cam. I have recommended it to people several times.

[@goldsgarage8236]

Thanks, we were pleased with the results also. AG

[@dondotterer24]

Great job guys!

[@goldsgarage8236]

Thanks for watching Don.AG

[@kcsavers]

Along with the great power and torque, it sounds so good when put through its paces!

[@goldsgarage8236]

Thanks for your comment Alan. AG

[@doomman700]

One of the things we found with the 4-7 swap was better harmonics in the crankshaft. Should help bearing life.

[@doomman700]

If you run a Qjet like he does in SS you will find everything in the fuel system that is not perfect. My SS car sucks it way down there at 9000

[@goldsgarage8236]

Thanks for your comments Dooman.AG

[@dinoa9608]

Not sure if I missed a few frames of the video, but would be great to see a close up of any of the dyno graphs to follow the hp and tq numbers throughout the rpm range. Also info on manifold pressure at idle. Great build. Customer will be happy.

[@goldsgarage8236]

Thanks Dino, will work on that. I don't have a specific number, but there will be plenty of vacuum, the cam is not radical at all. Anything less than 230 degrees @.050" will provide lots of vacuum.AG

[@elainestamper3873]

Interesting information, good video! Missed any info on the cylinder heads

[@goldsgarage8236]

Thanks for commenting Elaine. The heads are PROMAXX 185cc. AG

[@488ci]

Excellent information and an excellent video 👍

[@goldsgarage8236]

Thanks for watching and commenting Ram.AG

[@jamesbruno5896]

Congratulations guys amazing numbers!

[@goldsgarage8236]

Thanks James, we were pretty pleased with the results.AG

[@TomSmith-cv8hk]

Thanks Austin for the Qjet info, worth mentioning. Q'jets can actually handle fuel pressure, Holley's get messy over 6 psi. Bloody hell guys, bolted a carb' on an adaptor and didn't check secondary operation. 🤕

[@goldsgarage8236]

Thanks for your comments Tom.AG

[@DarrellWatters]

Lol thought it was an actual square bore carb 😅 didn’t look 🤦

[@DesertRatFabrication]

Awesome Al, great video, motor sounded really good😀😀

[@goldsgarage8236]

Thanks Desert. We were pretty happy with the results.AG

[@billhendon1017]

Nice ! Sounds good!!

[@goldsgarage8236]

Thanks Bill.AG

[@DeanStewart-t4v]

Another very interesting video..... like it.

[@goldsgarage8236]

Thanks for watching and commenting Dean.AG

[@ws2664]

That was really good, but I'm waiting for the video where you swap the 1.5 intake rockers to the 1.6 rocker ratio, I'm thinking about doing that but I want see if there is a big enough power gain to warrant the extra cost.

[@goldsgarage8236]

Thanks Bill. actually this engine had 1.6 rockers on the intake. On a previous video, we did change rockers on the dyno. On a 500HP engine, as I recall, we gained about 6HP. AG

[@ws2664]

@@goldsgarage8236 thanks

[@jesse5000]

Great video. So happy you got the numbers you did! The QJet should be a 750 or 800 cfm. Probably why you got bigger torque numbers. Was the 650 Brawler a dbl pumper or a vac secondary? I think it would have been interesting to run a 750 cfm sbl pumper (as someone else mentioned). You might be surprised!

[@goldsgarage8236]

Thanks Jesse, the Qjet is 750, and yes a bigger carburetor usually makes slightly better numbers on the dyno. AG

[@DarrellWatters]

The Brawler is a double pumper mechanical secondary carb, it’s one if 4 carbs I have on hand for testing incase the customer’s carb is a turd, I have a 650 Brawler mech dbl pumper, 750 Holley annular booster mech dbl pumper, 850 Brawler mech dbl pumper, and 1050 Dominator

[@steelcitycaprice.899]

😊 Awesome informational video!!👍🏼😎🏁🏁🏁

[@goldsgarage8236]

Thanks Caprice. Glad you liked it. AG

[@yarrdayarrdayarrda]

I've ran lots of combos over the years on the dyno, the one thing I'm certain of is you just never really know what the best combo is unless you test it. The open spacer on a dual plane is worth a few generally, but once in the vehicle it's a different story. If you run a divided intake, and you're using a spacer, use a divided spacer or you'll have low speed drivability issues.

[@davidreed6070]

Exactly the dyno doesnt proove what the engine wants in the car.

[@goldsgarage8236]

Good points guys, please keep the comments coming.AG

[@DarrellWatters]

You are right in that I’ve had conversations with Bill Little with his SS engine and the engine makes great power though out the rpm range but had to make changes as the 60’ times were slower, sometimes he changes the collector length and merge collectors to help the car launch

[@pockets5628]

You should show a close up of the dyno numbers, so the rpm of the torque and hp can be seen. And also overlay the graphs, compare the results. Overall power is more important than just peak numbers. For acceleration, the engine that makes the highest average power from the rpm drop point on the shift to the shift point will accelerate the vehicle the quickest.

[@goldsgarage8236]

Thanks Pockets. All good points, we could have done better displaying results. We will work on that.AG

[@tyrvidar]

great stuff

[@goldsgarage8236]

Thanks Austin.AG

[@kainehebert6173]

Which promaxx heads are these? Great results. Love the channel.

[@goldsgarage8236]

Thanks Kaine, these were the 185CC intake runner PROMAXX. Second set I have used and will use them again. AG

[@kainehebert6173]

@goldsgarage8236 that's impressive numbers with a relatively mild cam. Attributes of a good cylinder head and well put together engine combo. Thanks again!

[@billlittle4285]

28:56 There is no fuel in the bowl on wot, it's amazing why it works, what happens on a 600 horse engine....Mmmm , fuel for thought lol. Thats a first showing that Austin, very interesting.

[@patrickm.8425]

That's why you need larger and larger fuel pumps that can keep up!!

[@billlittle4285]

@patrickm.8425 exactly

[@davepilling3134]

Would you use the 1202 cam again ? I was expecting higher results considering the other mods. Another great video Allan.

[@goldsgarage8236]

Thanks Dave, compared to a similar 350 that i built recently, it made about 10-12 more HP. That is about what we were expecting. Yes, we will use it agian, there is also another version with bigger numbers we might check out. AG

[@salvatoregiovanni8967]

Really enjoy the channel. Just some constructive criticism. I’d like for you to post up the dyno graphs on the screen (as an actual photo) within the video. Preferably showing the overlays of the different curves. Just telling the peak numbers often doesn’t tell the whole story. Dyno overlays are really nice to see.

[@goldsgarage8236]

Thanks Salvadore. valid point, we could have done a better job of displaying the results. We will work on that in future videos.AG

[@ChevyMustang1]

Another great video my engine made 5hp more with a K&N 3" open element and the filter top at A&J Automotive (Armstrongs) I'm sure Darrel and Austin know Alyn abd John Armstrong anyway keep tge great videos comeing

[@goldsgarage8236]

Thanks for watching and commenting Chevy. Good info! AG

[@DarrellWatters]

I’ve tried that air filter combo in the past and found less impressive results as it made less power and torque, but every engine combination likes different things, so what works on one engine may not on others.

[@kevinclemence4661]

Quick question Mr G. I may have missed it however I'm curious to know if you're using any kind of header collector extension.

[@goldsgarage8236]

Good question Kevin. It might of been worth a try but we didn't get to do that. Based on the data we had, Darrell felt that would cause over scavenging of the cylinder. AG

[@kevinclemence4661]

@@goldsgarage8236 Fair enough. Obviously more thought into it than just my asking a question. That said, it never ceases to amaze me how down on lower RPM output a car "feels" when running the stubby collector on the way to the muffler shop! I'll bet though that in your case, the torque would see a bump. It would require re-jetting I would think. Thanks for the reply Alan. Keep up the good work.

[@DarrellWatters]

It was on verge of over scavenging the way it was and like Mr. G said it would have over scavenged the engine which would look like a lean condition which would have made is over jet the carb to make up for the fuel going out the exhaust

[@kevinclemence4661]

@@DarrellWatters I'm curious to know what the indicators were for this "over-scavenging". If it's lean with a collector extension, then adding more fuel should make more power. Unless of course it's spot on to begin with. And with a stubby collector extension (and I assuming this mind you) I would tend to think this wouldn't be the case. A Chevy like that particular spec generally falls into the 16"-18" collector length for best torque. Programs such as PipeMax will suggest this.

[@DarrellWatters]

@@kevinclemence4661 thanks for the question, I’ve talked about the BSFC on our videos, but I do check the BSAC which is lbs of air/hp/hr, I like to see this reading under 6.7-6.8, this engine with no collector extensions just touches 7 at the upper RPM. If we had put extensions on it would effectively lean the engine out, and yes you are correct that we could richen the mixture to compensate, but it would just use more fuel and make basically the same power. I’ve had to do this in the past with customer headers, but it does throw off the dyno numbers which makes it harder to tune, which in that case, I start pulling spark plugs to verify the mixture.

[@edpetrocelli2633]

Most people haven`t driven a 400+hp car, your customer is gonna be surprised when he stomps it.

[@goldsgarage8236]

Thanks Ed. That is a great point.AG

[@KenheinrichHeinrich-fr9vw]

Hello AG this is ken. I just put a 400 sbc together for my 68 camaro . I currently have it on a test stand . I notice when I accelerate the motor hard it puffs blue smoke . I believe the rings are not 100% sealed to to the cylinder walls and thats the cause. Do you think they will seal up after I get 1200 or so miles on the motor or do I need to tear it back down to re-hone the motor? The motor was honed by a local machine shop. Thank you

[@goldsgarage8236]

Thanks for the question Ken. Usually MS hone jobs are pretty good. Since you have it on the stand, you might check compression, and leak down if you are able. What about valve seals? It might just be one cylinder? I would also remove spark plugs and see if any are oil fouled. Remove the exhaust and look into the exhaust ports, do you see evidence of oil in any cylinders? Even the sealing of the intake manifold, on the lifter valley side can cause this. Hope this helps. Let me know what you find. AG

[@DarrellWatters]

I had a similar instance with a past customer who did the exact thing you are doing, they even found engine oil in the plenum of the intake they rebuilt it 3 times trying to solve the problem, they brought it to the dyno and after the break in and tuning session there was no more blue smoke or oil i the intake, so most likely your rings aren’t sealed, you need load on the engine to force the rings out against the cylinder wall for them to seat properly

[@hardtail-gy8dk]

Does Austin have a shop and work on others?

[@goldsgarage8236]

Austin, can you please reply to this question? AG

[@DarrellWatters]

No Austin and I both have regular jobs and do this as a hobby, he does build a small amount of engines and transmissions and is very good, but it’s not his main source of income

[@toddbrown2236]

Excellent video, Allan. I'm very impressed with how much power the engine made. It makes me wonder why it made so much more horsepower than my Pontiac 389 with similar compression ratios and I'm interested to know your thoughts. If you recall my 389 produced 357 hp and 422 ft/lbs of torque and that Chev engine produced 57 more horsepower (414). I also noticed you were running it at a higher rpm than the Pontiac. Was the hp difference due to the higher rpm or the cam, or a combination of the two? Just curious. Also, I didn't notice any data in the video with the different air filters you tested. How did the smaller air filter affect the air flow with respect to performance? Thanks again for the video.

[@goldsgarage8236]

Good question Todd. The results we achieved with your Pontiac were consistent with all of our previous Pontiac builds. The three main factors that impact HP and torque (per cubic inch) are compression, cam timing and air flow (cylinder heads and intake manifold) Compression and cam timing are easy to change. The difference is in the cylinder heads. If we had tested this 355 with stock cylinder heads and intake manifold, the results would be close to your 389 with stock heads. With respect to RPM, valve timing (duration and LSA) dictate at which RPM the engine is most efficient. More duration would move the peak torque higher in the RPM range, and since HP=torque x RPM/5252, the peak HP would increase, however the trade off is that your engine would be less efficient at lower RPM, and less fun to drive. Cylinder head flow also limits the RPM. Hope this helps. AG

[@toddbrown2236]

@@goldsgarage8236 Thanks Allan. I'm still very, very pleased with my 389, and like I said during dyno day, its performance exceeded my expectations. I was just surprised at the numbers on this Chevy engine but until I read your comments I hadn't considered the heads. Thanks again. Your videos are always a source of new information for me and I thoroughly enjoy watching them.

[@patrickm.8425]

Big block torque? ROFLMFAO!!! I love me a good laugh, thanks, I appreciate it!! ha ha ha!! "This little 355 Chevy will run with the big blocks!" - ROFL!!

[@alleyoop1234]

What numbers does a L78 make?

[@DarrellWatters]

If you had that in a 70 Chevelle it would be comparable to a 396 but the 454 ls6 would beat it but terribly

[@markmcmullen1371]

good job 👍👍👍

[@goldsgarage8236]

Thank you Mark.AG

[@4speed3pedals]

I would put my faith in the Edelbrock VRS to be the best performer. Salty devils they are.

[@goldsgarage8236]

Thanks for your comment 4speed. AG

[@DarrellWatters]

Yes, you can make any carb work well if you spend the time tuning, my Max Wedge uses the Carter AFB carbs which is what the Edelbrock carbs are based on, it works fantastic

[@b_hall]

What size are the runners on those heads?

[@goldsgarage8236]

Thanks for the question B. They are PROMAXX 185 cc. AG

[@joe-hp4nk]

A 4 7 swap cam means you go from cylinders 5 and 7 firing to cylinders 2 and 4 firing. Seems to be an exercise in futility.

[@goldsgarage8236]

Good point Joe, however we did achieve better results compared to similar engines with the conventional firing order that we have tested. AG

[@jefferycoleman3781]

For anyone that cares, Heres what Desktop dyno 2000 shows for this combo with open headers. With exhaust mufflers, its still right at 400hp. I was hoping I could see the data for the real dyno to compare but this has very similar peak numbers at 418/423!! Cool RPM HP TQ 2000 143 375 2500 185 388 3000 228 399 3500 275 412 4000 320 420 4500 362 423 5000 394 414 5500 414 396 6000 418 366 6500 410 331 7000 392 294

[@goldsgarage8236]

Good work, thanks for doing this. Your Desktop Dyno is very accurate. AG

[@DarrellWatters]

That’s with the 650 Brawler

[@jefferycoleman3781]

@@DarrellWatters What are you referring to? Desktop dyno just has input for cfm, not brand or carb type. The 650 brawler carb flow more than an edelbrock 650. The Brawler is a great carb!!

[@DarrellWatters]

@@jefferycoleman3781the dyno numbers I posted are for the Brawler carb

[@jefferycoleman3781]

@@DarrellWatters Its covered up with a popup from 4900-5600rpm but from what I can see it is very close to the desktop dyno results, I have compared it to many dynoes, its very accurate IF you make sure everything is accurate. BTW I love those brawler carbs..

[@3quartergarage]

What are the head specs

[@goldsgarage8236]

Thanks 3/4. They are PRX9183, 185cc intake runner volume, available in 64 and 72 cc Combustion chamber volume. PROMAXX also has a bigger one, i think it is 200cc, maybe more. AG

[@jimbarton8055]

4/7 swap makes more of a difference on a single plane intake or tunnel ram.

[@goldsgarage8236]

Makes sense Jim. Maybe we will try it. AG

[@floridaroadracerguy]

LS engine is 4/7 and 2/3 swap compared to SBC

[@goldsgarage8236]

Thanks DKR. you are correct and i should have mentioned that. Why do you think they didn't include the 2/3 as well? AG

[@joe-hp4nk]

A 750cfm would have made more power.

[@goldsgarage8236]

Thanks Joe, you are probably correct. i wish we would have had time to test one. Often over-carbureting does give better results on the dyno, however not necessarily in the car. AG

[@racerd9669]

Why are you not looking at EGTs, if you would compare the EGT between the 3 cards, you would throw that Edelbrock carb in the junk bin. I have seen so many of them that run EGT of over 1600degs.

[@doomman700]

Sounds like someone needs to learn to fatten up a Carter type carb

[@ericuncapher9922]

So how much more or less power than the classic 18436572 firing order?

[@alleyoop1234]

Easily remedied on a Eddy/Carter!

[@doomman700]

@@ericuncapher9922minimal , you won’t feel it. The engine may last longer because of better harmonics.

[@racerd9669]

@@doomman700 Sounds like someone has never had an engine on a dyno. When you have 5 cylinders running at 1150 to 1200 degs and 3 running at 1400 to 1500 degs , on a dual plane intake. And that was after trying 3 Ed carbs. You tell me how to fix it. A Quick Fuel carb fixed it. All 8 cylinders ran between 1150 to 1200 degs.

[@johnhughes738]

Al why dont you build a little 283 and see whats the most hp that you can get out of it i was not impressed with the one power nation did i believe that at least 315 could be gotten out of one i built one years ago not to great on bottom end but good Lord on top end she was a screamer it was stout

[@goldsgarage8236]

Good question John, same stroke as a 302, however the small bore tends to shroud the valves, in fact you cannot use the 2.02" valves as they would hit the block, so the HP/cu.in would be less. I grew up with the 283, then 327 and they were pretty cool in the day. For street engines, unless it it s a numbers matching restoration, HP/$$ is the motivation. It actually costs less to build a 350 as there are so many parts available. If someone wants a 283 build, I am game to do it. AG

[@johnhughes738]

Ps i think that was impressive on the 350

[@goldsgarage8236]

Thanks John.AG

[@jaygooch1190]

Take that POS edelbrock carb and scrap it

[@DarrellWatters]

It worked just as good as the Brawler, in this application 👍🏻

[@tonydowns9424]

What did air fuel say?

[@goldsgarage8236]

thanks Joe, good point! AG

[@goldsgarage8236]

Sorry for the previous reply Tony, i must have the comments mixed up. As to your question, we were not able to measure A/F specifically. We used BSFC, (Brake Specific Fuel Consumption) lb./HP hour, which is a measure of the efficiency of the engine, Fuel Consumption, and spark plug readings, and of course HP and torque results for tuning. The average BSFC was about .440lb./ HP hour, which is a good number for this kind of engine. AG

[@ibraunchy20-vn5kd]

I built similar , 60 over 350 4 bolt hyperrectum flat tops, Promax 225 cc heads 208 intake vlvs, Edelbrock RPM air gap , comp 284H cam , pistons are 0.015 in the hole with a 0.015 crush head gasket , proform 750 carb mech secondary's 4 hole spacer, makes 454 hp with 4 spd and 4.10 gears in a 3100lb car ,it is pretty quick

[@goldsgarage8236]

I am sure it would be fast, thanks for the info.AG