Dennis, cam question
 

Dennis,

I've narrowed my cam choice down to two cams for my 454 Mag MPI (Gen VI):

1. GMPP #24502611: 211/230 [email protected]"; .511/.540 lift; 112deg LSA.

2. Comp Cams 01-414-8-112: 218/224 duration@ .050"; .511/.511 lift; 112deg LSA. (This cam was recommended to me on Comp Cams' hotline.)


On Dyno 2000, these cams produce almost IDENTICAL power curves. The GM cam is about 5 lbs-ft higher from 2000-3500 rpm and peak power is about 6hp higher at 5000rpm. Obviously, these numbers are too close to assume that Dyno 2000 is dead-on accurate. Based on your experience, would you choose one of these cams over the other? Does Comp Cams tend to have faster opening and closing flanks than GM, which might generate more power but not show up in the numbers? Any problem using the stock valvetrain with either cam? Any other advice?

One more note, Dyno2000 shows that the Comp Cam has no overlap (-3.0 deg) and the GM cam has -3.5 deg, so I'm assuming water reversion should not be a concern.

Ric 232
 

I really like the Comp Cams 218/224 but I would order a cam with a 110 LSA. What does the dyno program say when you tighten the LSA?
I would install it with no advance for a more noticable performance gain.

I don't know why Chevy designed a camshaft with 19 degrees more exhaust duration than intake. They must have some reason but nobody else has ever done it!
As far as I am concerned the longer you hold the exhaust valve open the more water you are going to get back into the cylinders at an idle.

I hope I am right about that. But it makes sense to me!

Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE

Dennis,

The guy I talked to at Comp Cams stated specifically that I should order w/ a 112 LSA to avoid water reversion. He said this w/o me asking him.

Anyway, when I change the LSA to a 110, the peak torque goes up 5 lbs-ft @ 3500 rpm and 13hp @ 5000, 21hp @ 5500 (higher than I think I want to run). There is almost no difference between the HP graphs with 112 vs 110 until you reach 5000rpm.

Rick, have you considered a 502/502 (ZZ502) camshaft?
.527" / .544" 224* / 234* not sure of LSA

I am going to run this in my 454. Stock valvetrain will work OK, but I am installing Comp Cams springs.
If interested, I can get you a good deal on a new, pull-out cam.

Thats very similar to the Edelbrock Torker 2 flat tappet cam that I use. 224, 232 at .050, lift .527, .553 at 114 and I install it 5 advanced. Works very good in my 468's with no reversion.

These cams are way too small to worry about reversion. ;) I would go with the comp on 112 CL for your application based on the r's you want to turn.

I've got some experience with the GM 454HO cam that you list. I also did the dyno 2000 thang and was impressed with the power I was 'supposed' to pick up (almost 80hp difference at 4600rpm). I installed this cam and Gil manifolds and only picked up 2 mph. Was kinda dissapointed. It pulls waaaaaaaay harder down low, to the point i can blow out my prop fairly easily, but at 4200 rpm, it poops out. It also has a very boring, smooth idle. My friends stock 454 mag idles 'badder'. Might be my heads tho, i'm running the Vortec heads, maybe the rect port work better with this cam.? Any comments on this Dennis? I've been toying with the idea of some Edelbrock marine aluminums now......:p At what speed does the need to go faster go away???:D

At what speed does the need to go faster go away???:D [/B][/QUOTE]

NEVER:D

Good cam for the Vortech heads.
 

Madmax,
I bet that is a good cam for the Vortech heads! No, I wouldn't go with the rectangle port heads. They are just too big for anything but a monster motor. The Edelbrock marine heads are great (hard anodized aluminum and inconnel exhaust valves) but you would have to change the cam again to realize a performance increase.

JDNC1,
I agree that the cam is way to small to worry about reversion. I think Rick is going to be disappointed with the small/if any performance increase. It is very hard to improve engine performance without increasing engine speed.

Formula31
I rebuilt a few 454 engines for a winter project one year and installed the cam you suggested and they worked very well. A really good replacement for the stock camshaft with a good performance increase (also very reasonably priced!).

Dennis Moore

Dennis,

What kind of LSA would recommend for naturally aspirated 540 cubic inch engine with a cam that has something like 234*/240* (about .600" lift) ???

Thanks,
Mark/KAAMA