cam question

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joec

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Hi, new here to the forum. In building a 522 bbm, victor max wedge heads unported,13.5 comp,max wedge intake, original afb carbs. What would you consider using for a roller cam to turn to 6500 rpm? Already have recommendations, just trying to find out what would be suggested by folks who have done this already.
thanks Joe
 
Need more info to do a really good job on the cam choice but you probably want something in the 270 range for duration with .650 to .700 lift depending on your rocker arms and springs.

I have a fairly wide selection of used roller cams left over from all of the dyno testing I do so if you want a good deal on a cam just shoot me a PM. I have several cams that will work well with your combo.
 
Andy,thanks for the reply. The engine presently has a comp roller 275/282 108ls 660 lift and it peaked at 6000 with 636hp and 700ft lbs at 3200. The reason i asked is because I thought it should have been higher.I think the manifold is the restriction but its in a 64 max wedge car and have to keep it for appearance.I noticed all catalog cams are ground on a tight lsa 105 to 108 and starting to wonder if with strokers that the lsa shouldnt be wider like 112 to 116.There was no sign of reversion it just didnt like rpm.Kind of like your 470 build more questions than answers although I think you have answers I dont.
Anyone with ideas please jump in.
Also the heads have not been ported.

Joe
 
joec said:
Andy,thanks for the reply. The engine presently has a comp roller 275/282 108ls 660 lift and it peaked at 6000 with 636hp and 700ft lbs at 3200. The reason i asked is because I thought it should have been higher.I think the manifold is the restriction but its in a 64 max wedge car and have to keep it for appearance.I noticed all catalog cams are ground on a tight lsa 105 to 108 and starting to wonder if with strokers that the lsa shouldnt be wider like 112 to 116.There was no sign of reversion it just didnt like rpm.Kind of like your 470 build more questions than answers although I think you have answers I dont.
Anyone with ideas please jump in.
Also the heads have not been ported.

Joe
Click to expand...

The intake manifold will hold you back some but the major bottleneck is the heads. Unported the Victor head has notoriously bad airflow. The heads need to be ported. The OOTB Victor head (standard port or max wedge) flows less than the OOTB Edelbrock RPM head to .400" lift and just barely out flows the RPM at .500" lift.
 
According to edelbrock the victors flow roughly 20-30 cfm more from 400 to 600 lift than the performers and close to the trick flow. Why is Andys 470 with 271 @ 50 giving up the ghost early with trick flows?I think i am seeing pattern but cant understand.A 426mw
stocker w/stock(nhra legal cheated up) holds rpm longer as Andy said.

Many cyl head porters dont care about low lift flow in fact they try to lower it
Please lets continue this discussion for the sake of knowledge.
Thanks Joe
 
The cross ram intake is a major tuning problem. If you pull that intake off and put a Super Victor on there with a Dominator carb you'll probably pick up 100+ hp. That seems like a good cam for a big engine with good heads and a Dominator carb. I have no idea why it doesn't work with the cross ram other than the fact that cross ram intakes don't flow very well.

I do not know how the Stock guys get the MW cars to run as fast as they do. I guess they just work on them for hours and hours. I've run MW engines on the dyno before and they have all been complete dogs. We always see huge power increases when we ditch the cross ram intake and install a good single 4bbl intake.
 
joec said:
According to edelbrock the victors flow roughly 20-30 cfm more from 400 to 600 lift than the performers and close to the trick flow. Why is Andys 470 with 271 @ 50 giving up the ghost early with trick flows?I think i am seeing pattern but cant understand.A 426mw
stocker w/stock(nhra legal cheated up) holds rpm longer as Andy said.

Many cyl head porters dont care about low lift flow in fact they try to lower it
Please lets continue this discussion for the sake of knowledge.
Thanks Joe
Click to expand...

I better like the question, "Why is Andy's 470 making 675HP (and yes, I think Andy can make more) while your 522 is making 636 HP?" Andy has given you one reason.......the intake manifold.

Here is another reason, cylinder head airflows. I don't care what Edelbrock claims, this is how they compare........all on the same flowbench.......all OOTB.

Lift... EDL RPM #1......#2.....Victor #1.....#2......#3......TrickFlow

.100.............73........74..............60.....68......68.........70
.200............148......149............120....141....129........150
.300............209......211............181....204....190........221
.400............254......253............237....246....243........276
.500............276......280............276....277....290........322
.600............287......292............314....305....315........336
.700............291......292............314....324....313........333

Heck, we have a single 4bbl 451 with our ported Edelbrock RPM heads (349cfm) that makes 679 HP @ 6,000rpm and 771 HP @ 7,000rpm.

The 522 is running out of air, not camshaft duration.

What kind of exhaust system are you using? Not cast iron Max Wedge manifolds?
 
IQ52,the car has 2 1/8 hooker adj headers w/no exh.
Your flow testing is interesting, actually amazing compared to their specs.
Have you ever tried a wider ls cam? Torque isnt a problem just upper rpm hp with that manifold/head combo.
 
Yes the lobe separation angle will effect the horsepower but not so much the way you think. Here are two applications on the dyno, changing the LSA only. I widen the LSA for mostly these reasons on NA engines, idle quality and vacuum.

http://www.superchevy.com/how-to/engines-drivetrain/0905chp-camshaft-lobe-separation-angle-performance-test/

http://www.superchevy.com/how-to/engines-drivetrain/1506-lobe-separation-angle-explained-and-how-it-affects-horsepower/

People on this forum are tired of hearing me say this, but here it is again.

Daddy told me when he was building engines in NASCAR, "Jimmy, there are three secrets to building horsepower. The first two are cylinder heads. Third and most important........cylinder heads!"

You're outta air sir.

I ran a 451 with iron heads and 290 cfm. It made 621 HP @ 6,100 rpm. Now that you know what unported Victor heads really flow, check any cfm vs cubic inches and rpm calculator and see what rpm your engine is done.
 
If you go read the old magazine articles that I wrote on my 505 inch dyno mule you'll see that the engine made 625 hp with a cross ram intake but picked up to over 800 hp with a ported super victor intake and a Dominator. Same basic shortblock, same identical Indy EZ heads. An out of the box cross ram is horrible. Evidently some guys know how to port them since some MW cars fly, but right out of the box they stink. Borrow a Super Victor intake and a Dominator carb and see the difference. Then you can figure out where to go from there.
 
IQ thank you for the cam reads,however when your dealing with a not so heavy car and making 630 or 700 foot lbs of tq. I think it might be beneficial to trade off some tq for a little more rpm/hp . a few years back I helped with a 340 70 duster started off as a 15 sec car. With a manifold swap(torker to dual plane)cam swap232/242 112hd from a 242/242 108 and tuning the car was in the low 12s.We went back to the 242/108 and lost 2 tenths.Put 232/242 back in, came right back w/same4000 stall converter.I wondered why it was quicker with the 112 vs 108 .
Back to the 522
I know the heads/manifold are killing it, but to get it to rpm a little higher i thought spreading the lsa w/less int duration might be a good compromise.
Thank you, Joe
 
Andy, thanks for the reply I will do as you suggested and try it . The car is an original max wedge car and the owner wants to use the cross ram(for nostalgia)but I can try the sp/dominator combo.
Thank you, Joe
 
Also if you took away the ex split on a thumper I thonk it would peak alot sooner w/less hp but more torque. Gm copo cars w/o supergargers are I think mid 230s int 270 exh, not single pattern . Just trying to figure it out.
 
Time to sandpaper my lips and staple them together......I hear they will grow that way......well that is what my 8th grade science teacher told me......right Rob (RRR)
 
IQ52,sorry didnt mean to aggravate you. I know more flow is more rpm/hp.I know heads/manifold are the bottleneck. Your a pro im not .My thoughts were given the heads otb no porting why couldnt you raise the rpm with a cam, not that i would do this,just trying to discuss why, for me and other non pros out there.
Again sorry and thanks
Joe
 
Joe, you can raise the rpm right now, just leave it in neutral it and will wind higher but not make any horsepower because there is no load against it. No load, no torque, no torque, no power. HP=TQ times rpm divided by 5252.

Or just keep your foot in it under load, at a point it will keep winding higher just making less horsepower. This is because the heads/intake won't let any more air in no matter how big the camshaft is. The more rpm the more air is required to maintain that rpm. When the heads/intake are all done, the higher you wind it the more the air has to be shared for each rpm. The less air/fuel per rpm the less power developed per rpm. This is one reason the power drops off at a certain rpm. The less cfm/rpm the less horsepower. There are more reasons, one is coming up.......

But first, again. The cam could be likened to an inlet valve on a pipeline. If you have a 2" hole (heads/intake) feeding a 4" valve (cam) you can put a 5" valve (bigger cam) on there but the 2" hole wont let anymore air/fuel into the the 5" line. It won't wind any higher with power, it doesn't have the air/fuel to make any more power.

Your cubic inches and cam are big enough to max out your intake and cylinder heads around 6,000 rpm. After that, its down hill.

You can put stock iron heads and intake on your 522 engine with the present camshaft and it will make way less peak power and at a lower rpm than it does now. Why? Why is it's peak power around 4,000 rpm? Why won't it spin much beyond 4,800 rpm? Come on darn it, it's got a big cam! Well, that piston is sucking so hard on that intake valve that it's veins are standing out on it's neck and it's face is purple. It's mach index is way up there and the VE is dropping dramatically.

Then, the higher the rpm the more parasitic drag in the engine. The more parasitic drag the more power it takes to maintain the rpm........and the horsepower to the flywheel drops further still. Less power to the flywheel and the car will still accelerate but at a slower pace.

Quick, shift it into it's higher torque, lower rpm range! Taller gears, bigger tires.

One thing for you to do is change the valve lash and see if the engine wants a bigger or smaller cam. Tighten the valve lash....bigger cam. Open the valve lash....smaller cam. Tighten the intake/open the exhaust. Open the intake/tighten the exhaust. You'll see some incremental changes but nothing drastic. You might change the peak rpm 50-100 rpm or so, but I believe you may just gain or lose a few horsepower at the same rpm.
 
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