there are some other options for big cams and keeping vacuum levels at a level that is tolerable. i have a very aggresive cam but i am using rhodes roller lifters and have 13 inches of vacuum w/ an idle of 950 rpms.

 

Just got a new Comp custom grind cam installed in my 96 Trans Am and it is awesome. Cam is 236/245 112

However, I have a 383 Stroker with Stage 3 heads and 4.11 gears.

The street driveablity is excellent. Brakes are fine and the power is incredible.

 

Yup ... what Rich said ... you have to consider the brakes, nothing will tick you off more than having marginal to poor brakes, makes the whole experience ... miserable.

I also am running that 224/236 on a 114lsa in a 383.
I also had to set my idle up to 900 rpm, which makes for some rather aggresive "stop light creep" if you let your foot off the brake.

I also added timing, 6 degrees in the "closed throttle spark advance" table. On top of that I also added 3 degrees of timing in the 400 - 4000 rpm table as well. All in the pursuit of enough vaccum.

I now see 12 - 14 inches of vaccum while coasting and 9 - 10 inches at a dead idle. Enough, but only just barely. In a 350 ci engine, ??

Your altitude is also a factor, sea level air will allow you to run a much bigger cam than what I can up here at 3,500 feet.

Just trying to get good information out there.

LWM

 

Why not install vaccum canister to give you the vaccum you need for the brakes and not have to idle the car up?

 

I thought about it, but the job of finding space for even one more piece of equipment under the hood made me want to avoid it if at all possible!

Rich

 

I think it's being tried...

http://web.camaross.com/forums/showt...ghlight=vacuum

http://web.camaross.com/forums/showt...hreadid=249542

 

Springs , studs, pushrods lifters and rockers all need to be rated to handle the spring pressure required to keep you out of valvefloat with an agressive cam. If you skimp , you will be breaking parts.

I just recently (few months now) added a GM 847 cam to my car (234/242 .050 ). I made sure to buy an H-11 steel spring ( H-11 = higher silicon content lasts longer and stronger) . I didnt though upgrade my pushrods( already had ARP rocker stids, guideplates, cc pro mag steel 1.6 rockers and added CC pro mag lifters)
I just used the 3 peice hardened for GP s units. I learned within 100 miles that these pushrods would not hold up to 400#s of spring pressure for long, snapping a couple. I added the Comp 1 peice chrome moly .080 wall thickness pushrods and have a couple thousand miles on em now with no problems (but a lifter is now complaining).

 

I'm running a Comp XE 230/236-112 cam. It's not as extreme as the 306, but then I don't think the HP suffers too much for it. I am running Comp 987 springs, Comp Pro-Mag 7/16" stud non-self aligning rockers, 7/16" studs (obviously), Trick Flow chrome-moly one-piece pushrods, new OEM replacement Comp lifters, Comp guideplates, etc. The top end was not cheap, but I'm not worried about it coming apart at high RPM. The XE cams are more abrupt, but are still safe with good valvetrain parts.

Driveabilitywise, the 230/236 is pretty tame. It does have some cam surge at low rpm, but it's pretty easy to avoid problems just by driving a bit differently. It's much easier to drive if you just get on it, instead of babying it.

I don't have any problems with brakes, and I wouldn't hesitate to drive the car in stop and go LA traffic. It's a pain because of the M6, but still manageable.