[paulm]

I am running a GM 962 cam (Hyd 224/224 .450/.460 114) in my 383. I have 10.5:1 compression and Edelbrock Performer RPM heads. I'm going to swap to a Holley Stealth Ram intake and since I'm in there I was considering a cam change.

I was thinking about a GM 182 cam (Mech 242/254 .459/.485 116), how do you think that would run in my HSR intaked 383, 2004R & 3.73 gears?


P.S. I guess the "182" is AKA the 178 cam, came in 70 Z28's.

[Doug F.]

What ECU?

[paulm]

C950, Version 3....Glad you popped in Doug!

I'm not sure about using the GM cam anymore, been talking to Ultradyne trying to design the "right" solid cam to run given my 10.5 compression, 2000 stall and EFI. The tech guy there is concerned about getting too big of a cam as he thinks that this may cause the ECU problems, too much for my stall, etc.

Doug, what is your experience with the size of the cam vs the tunability with C950? Would duration number of 230's or 240's impact tunability?

[camcojb]

the duration numbers affect the vacuum. When you swap from a mild cam to a larger one you will be re-tuning areas (especially idle) as the vacuum will change. However, I've tuned cams much larger than what you're looking at with EFI, no problems. Doug can fill you in on the limits of the Holley 950, but I'm sure it can handle that cam.

With that said, I'd opt for a modern grind. The factory stuff was cool in the day, but the new stuff is usually even better. Also realize that similar duration numbers can have completely different idle and vacuum characteristics, depending on lsa, where the cam is installed, and timing events.

Jody

[paulm]

In Speaking to Lunati, Crower and Ultradyne given the following:

* 383 10.5:1 compression w/aluminum heads
* EFI
* 2000 stall
* 3.73 gears
* The fact that I don't want to lose any drive-ability or much MPG
* Not looking for a race car, just trying to get a bit more power/efficiency with a solid

They are all coming in around 232/240 @ .050 .490/.500 on a 112/108.

This seems like a good spec for a solid flat cam to me (I'm clueless on picking cams though) as it doesn't seem that much bigger than the 962 cam. The Ultradyne guy made the biggest stink about EFI. The cam specs above don't seem like anything exotic and I'm sure that many many people run much bigger cams than this with C950 and no problems, so I'm not sure why he thought it was a big deal. I probably run a much smaller cam than most in my camaro engines.

[camcojb]

Originally Posted by paulm

In Speaking to Lunati, Crower and Ultradyne given the following:

* 383 10.5:1 compression w/aluminum heads
* EFI
* 2000 stall
* 3.73 gears
* The fact that I don't want to lose any drive-ability or much MPG
* Not looking for a race car, just trying to get a bit more power/efficiency with a solid

They are all coming in around 232/240 @ .050 .490/.500 on a 112/108.

This seems like a good spec for a solid flat cam to me (I'm clueless on picking cams though) as it doesn't seem that much bigger than the 962 cam. The Ultradyne guy made the biggest stink about EFI. The cam specs above don't seem like anything exotic and I'm sure that many many people run much bigger cams than this with C950 and no problems, so I'm not sure why he thought it was a big deal. I probably run a much smaller cam than most in my camaro engines.

I'd think that because he's thinking of a factory non user-tuneable system (well they're tuneable, but generally the end-user can't do it himself). These aftermarket units are adjustable and really no big deal at that size in my opinion.

[paulm]

Jody, so how do think the HSR intake will work with this cam spec?

[camcojb]

Originally Posted by paulm

Jody, so how do think the HSR intake will work with this cam spec?

I think it'll be fine, but I usually run a bit more lift. EFI in general picks up low-end torque and that manifold will add even more than normal in the low to mid-range areas. Should sound good and run great.

Jody

[paulm]

Originally Posted by camcojb

I think it'll be fine, but I usually run a bit more lift.

Jody

How much lift?

[Doug F.]

Tuning, no issue. They obviously don't have a clue about aftermarket EFI which is typcial. I "schooled" a guy at comp once after picking a cam then telling him it was for an "EFI" car. He couldn't believe it. A stock ECU that you don't want to touch, another story.

You have a little conflict. Drivability but I'd be a tad concerned about that compression and small cam. If you don't want to loose drivability, I'd say their specs of 230-235@.050 on a 112 LSA is a good bet without being too much of a pooch. It will still thump a little.

We are coming out with some new solid flat tappets at work for Lunati. I've tested them a lot and they are VERY nice. I'll have to look at the specs tomorrow and see what matches up with your combo.

[paulm]

I'd appreciate that Doug!

I spoke with a guy from Lunati and he was recommending about the same thing, something like .050 232/242 .490/.501 on 112/108. He said that it would have to be a custom grind and gave me the numbers.

[Doug F.]

The new Voodoo series cam coming out is 233/241@.050 and .505/.520 lift. That is the smallest in the line. It comes standard at 110 LSA and 106 ICL.

I've dynoed this cam and driven it in a 350. I will say it had a pretty good thump to the idle though. More than your current cam I'm sure. It did idle ok though with a stock torque converter. From a dead idle it would melt the tires even with the stock converter. It would actually pull hard to 7k and even more.

A 383 should tame it down a little and I'd order it on a 112 LSA. We've tested these cams on a wider LSA and they actually like them. I'd say that size is the largest I would go and on the border. You'll know there is a cam in there from the sound, but it should drive nice with the stealthram.

[paulm]

Thanks Doug!!!

Funny thing is that everyone seems to be coming in around the same specs, roughly 232/240 .500/.500 112/108. I suppose now I have to figure out a way to be able to tell the difference between one company's cam and the other when they have virtually the same spec (just different ADV numbers).

[Doug F.]

Differences aren't apparent in any of the published catalog numbers. Differences are found in valve train stability. These new cams were designed with a pretty sophisticated software package with someone that really understands valvetrain dynamics and required limits. This results in proper valve train operation and life.

[paulm]

OK, so I should buy the Lunati cam huh???

Hey, the VooDoo cams are hydraulics....I want solid.