Hey guys,
I went to World Of Wheels, Talked to a guy from Comp Cams. He recommends the 292H with 987 springs and a 3200+ converter, here is my combo now:

350
10.25 CR
Double Hump heads, 2.02/1.60 , 76cc
292...244 @ .050---.501'' lift
RPM intake
700 Holley DP
TH350 with 3000ish converter
4.56 gears soon to be 390/410 maybe even 373s
25'' tire

I would like to get my heads to flow better and do a bowl blend? I figured since i have to get a machinist to work the heads for the bigger springs ill have them do the bowl work, I'd like to port my heads myself to learn how and experience this. Should i get a book on how to do it? what do i leave alone? I was thinking just to match the intake gaskey to the heads and cut there (not too much) and smoothen it out. Thanks for the replies, sorry its long

That wont do much for power, concentrate on smoothing out the bowls & guides.
Most of the power is 1" above and below the valve job, so clean up any sharp edges
where the seats were pressed in. Then narrow the guide bosses down. You could
then unshroud the valves in the chambers - do this before you have the valve job done
as its easy to nick the seat cuts when doing the porting with the valve job already done.
Just smooth things out around the seat - this will make the biggest diff. in flow & power
if youre just startin out. You can pick up 15-20cfm with bowl work which is about 25-30hp.

Standard Abrasives web site has a decent "How-to" section. Keep in mind they are in the business of selling stuff so they like to grind and polish a LOT. ;)

-Mark.

good lord they are still pushing the old magnum cams?

Call cammotion .. u will get something that has a little more exhaust lobe to account for head shortcommings.. (which, also exist on the intake).

I agree...the biggest gains are right in the valve bowl area. But, don't get carried away...a giant port with no velocity can hurt more than it can help. The biggest thing you are looking for is smooth airflow...something that needs work on nearly any stock head.
Also, what head castings are you using? 76cc heads are not double humps. To get a true 10.25-1 compression would require a domed piston with 76cc heads. Also, I would not use the 987-16 springs for the 292H cam. They are borderline too strong for a hydraulic cam and will cause undue wear. The recommended 986-16's are plenty...the 292H has a lot of duration but the lobes are not that aggressive, thus they don't need a ton of seat pressure.

Honestly, for a cam that big in that engine you should go for a stall of about 3800+,4.10's, and 28X9 slicks for the best launch at the strip.That cam just doesn't make much bottom end torque when used with a compression that low.

Sure the 3200 stall and a 3.73 will work with a 292 Magnum, but not that well.
With that combination I think that an Isky 280Mega Hydraulic would clean it's clock,even with a little more gear.Something like 3.73-3.90's with 26x8.5 will work well.

Isky 280 Mega
280 232 485 108

Or if you want more modern:
CamMotion PT# H2311-2362-10+5
231/236 486/501 110

[ 02-02-2004, 09:15 PM: Message edited by: thrasher ]

Thanks for the help,
I'm not completely sure on the heads, i know the compression is 10.25:1 but the heads are GM 2.02/1.60, I'm not sure if maybe they are camelback? what is the difference between the two? I thought they were the same.
Maybe the heads are 72cc? graemlins/clonk.gif i will pull the valve covers off this weekend for the casting #s but i thought it had the two hums on the head? How much would it cost to have a reputable shop do the bowl work? the reason i was going for the 292 is because i would like to stroke the motor later on and maybe get some different heads. I figure that cam would be good for a 377 or 383. Thanks again for the replies.
Adam

Travis- Thanks for the warning about the springs!

PS- My stepdad tells me that this cam will idle like cr@p on the street, would it really be THAT bad of an idle? thanks again

[ 02-02-2004, 07:30 PM: Message edited by: Drag67Camaro ]

Idle quality is often just a matter of opinion...one persons "idles like crap" might be someone elses "(*&^ that sounds awesome" :D
The 292 magnums idle is definately a fender shaker. The rest of your drivetrain is set up for a fairly serious cam any way. I'm partial to comp cams anyway because I have always had good luck with them...and I have used a lot of them. It all boils down to what you want.

DON'T cam your current motor by thinking about building another motor later on.
All that'll do is make you unhappy with the one you're building now and supply you with a used cam for your "all new and bigger" motor.
Cams and hyd. lifters are relatively cheap. Cam your 350 right and you may be so happy with it you won't even want to build a 383.
If you're looking for that thumpin' idle, just
use a smaller cam on 108 LSA (like that Isky 280 Mega) or have Cam Motion or Bullet or Comp grind one up on a 108 or even 106 LSA. Only takes 3-6 days for a custom ground cam from the time you order it.

Randy

Originally posted by ToyzRMe:
DON'T cam your current motor by thinking about building another motor later on.
All that'll do is make you unhappy with the one you're building now and supply you with a used cam for your "all new and bigger" motor.
I highly agree.I can't count the times that I have sean that exact scenario.

You will end up with a compromise cam that won't be good in either engine when it's all said and done.

If you are serious about making your engine run, before you even get serious about picking a cam get the heads sorted out first. You need to know what your compression ratio is (not just a guess) and what the heads flow after porting. I agree that the hydraulic Magnum 292H is probably not the best pick for a low compression 350.

IMO if you are willing to sink some money into getting the pockets cut for bigger springs, a good valve job, and the time/materials needed to do a home port you might as well look into aftermarket heads that will perform better for about the same cost. Even a used set of aftermarket heads are usually a lot better than home ported stock castings.

I just want to concur with what others have already said. The 292 magnum is famous for it's choppy idle, but also famous for being a pig off the line. I too am surprised Comp even recomended it. Go with the XE line and I would also recomend you go smaller. You could go XE284 if really wanted to get aggressive, but with a 350 the XE274 would probably work out much better. When the 383 project comes around, you can get a new cam and lifters for under $200, sell the old stuff on e-bay and come out pretty cheap.

If you are going to port the heads yourself for the fun and experience, go for it but you might want to think twice about paying to have it done. Get pricing on ALL the work and parts before you begin. You may very well find that you could spend a couple hundred bucks more and get an aftermarket head that flows way better than the double humps even after the port work.

Thanks guys, i guess i will keep the displacement at 350, maybe the 284H? My mom said she would buy me some TFS 23 heads that Eric recommended before, but that is only if i promise not to race at the track anymore, not implying to do it on the street. She is just worried. So when i take my heads off i will measure the dome and compare it to the 72cc and think of my CR.
Thanks again
Adam