96GS#007

Anyone have any experience with the "846" cam in their LT1 or 4?

Here are the specs from the GM Performance Parts website...
I'm tossing around the idea of upgrading from my HOT Cam (which I like but... ). The 846 duration is close to the same as the HOT Cam (2* more intake & exhaust) such that I don't think my idle quality will degrade. Basically I'm buying added lift.

Thoughts?

silver & red CE

What about the CC 305? Same basic spec but a 114 lobe sep angle, should have more low end torque and smoother idle.

http://www.compcams.com/Technical/Cu...ML/198-199.asp

BTW, lots of Impala SS guys love the 846. 305 or 846, I think you'll be happy.

Eric

96GS#007

Thanks for the feedback

With my 4.10 rear gears, I need something that'll peak around 6400 rpm. I'm willing to give up a little in the idle to 3000 range to gain 15 or 20 rwhp above 3000.

silver & red CE

So why no long tubes?

96GS#007

Visual inspection for emissions.

silver & red CE

Finally one advantage about living in Cook County. Don 't start ripping the Cubs, I'm a Bear fan

93 ragtop

If a little more lift is what you are after how about a set of 1.7 rocker arms. I believe it was Nathan that got about 15hp out of these compared to the 1.6 and using a hot cam.

LT4BUD

My CompCam 503 peaked at 6400 rpm......224/230 duration, .503/.510 lift with 1.5 rockers (I am using 1.6), 112 separation

http://www.compcams.com/Technical/Se...umber=07-503-8

Curveit

The Comp Cam; and most all after-market cams, will have less advertised(total) duration than the factory cams. They should make some more bottom end power, and have a better idle than the factory cams for a given .050 spec.

luvmy92

Hey Jim,

I am going with something similar in my 383 but don't have it running yet... here are the specs:

Comp Cam - 07-000-8 - 224/230 duration with the 3100 series lobes ( 3192/3194) and a 113 LSA. The lift numbers are .605/.622 with 1.6 RR's.

I should have some numbers on this in the next month or so.

Mike

silver & red CE

WOW, that's a lot of lift. What kind of heads are you running?

Eric

SPEED750

I would hop over to the camaroZ28.com forum. Those guys are serious gearheads. Do a search and you'll see a ton of specs on this cam and many others.

96GS#007

That's just sick My current head setup won't support those lift numbers. I'm maxed at .600

I know a lot of guys like Comp, but I like to use GM parts. Call it a silly quirk I have

I've thought about the 1.7 rockers. In my case valvetrain geometry is a concern because my heads have been surfaced. I'd just as soon avoid the hassle.

I think the 846 cam will give the added kick I want. The only question left is how different is the idle quality of it versus the HOT Cam. With tuning, the idle quality of the HOT Cam can be made such that there's just a hint that something is changed under the hood. I'd like to retain that same quality. I know, having my cake and eating it too. The car does see some street duty on nice days. When I take it to work I spend a lot of time sitting in traffic. With that as a given, cam lope that really rocks the car isn't really acceptable.

1996man

how much HP are you running 96GS#007 ?

96GS#007

363 to to the rear wheels with 4.10 gears.

FWIW, I don't drag race the car, only auto-x and open track events/schools on various road courses.

luvmy92

I am running the stage III ported heads from CNC. They are still flowing about 265 at .650" I think. My mechanic recommended this cam... I have no idea what kind of power it's going to make.

Mike

ToyC4

I'm a little new to this - how does surfacing the heads affect the valvetrain geometry? I guess surfacing the heads drops everything lower but is it enough to make a difference? I've had mine surfaced and I'm aware it will minimally bump up compression but I wasn't aware it affecting anything else. I'll be running the GMPP Hot Cam kit with the 1.6 rockers (as soon as the engine is back in the car).

96GS#007

You hit the nail on the head. Surfacing "drops everything lower". Without checking my notes, my heads have had .010 taken off. The 1.7 rocker arm has slightly different geometry than the 1.6 (or the 1.5 for that matter). Eventually you reach a point that you have to change to different pushrods It just keeps adding up.

Curveit

GM occationally uses after-market cams, and other parts;Crane roller-rockers, and some hi-performance heads for example. I believe that for a given lift, and duration at .050, a cam with smaller over-all duration numbers will give better idle, and low-end performance. They're faster acting on the lifters.

LT4BUD

CompCams offers some tools to check geometry.....I would assume others do too..

http://www.powerandperformancenews.c...ory_Code=PSHRD