Now that I have to pull one of the heads off the fresh engine anyway (see story here) http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=2;t=022043
I am going to go ahead and put the vortec heads on.
Any ideas what this combo should make with the vortecs. I was shooting for about 230-250 at the rear wheels.

.030 over 350 w/flat top Hyper pistons
Comp cams 268H .454 lift /.218 duration @ .50
Vortec heads with LT4 springs
Performer intake with Stock Q-jet
Stock HEI
Stock exhaust (I know, but I don't want to fool with headers right now).

Dwayne

anybody?

Dwayne

I'll take a stab at it and predict 330-ish

I guessed a 9:1 compression ratio and with DD2K3, it looks like 300HP and 360TQ. If you have an auto tranny I think you multiply the HP number by .8-.85 to get your power at the wheels.

You'd better check the compression on that engine. With my Vortecs I'm running ~10.5:1 static and 8.2 calculated dynamic with a 278/288 solid cam. Before the solid, I ran a 278 hydraulic for a similar DCR. I have to run 93 octane and the timing curve is critical to prevent detonation.

If you have a decked block or a thin gasket, your CR may well be too high for a 268 cam.

My buddy has that exact combination in a 72 Camaro, but with Hooker SuperComp headers. His car dyno'd righ @ 300 HP and 376 ft lbs. of torque on the Power Tour's chassis dyno.
That was with a 700R4 trans and a perfect tune. It runs HARD and has never had detonation problems. Never ran it on the track. If he did, I would guess low 12's with good traction. His valves are stock, but we back cut them and did mild bowl work on the exhaust ports.
Now would be the best time for headers!

I will say absolute minimum should be 360hp at motor. If an L79 327 made 350hp, and you added 23ci, muchbetter flowing heads, better cam technology. I think 360 should be easy. With headers, intake, carb and a properly tuned the combo should be able to break 400hp.

I recommend the headers now. Mush easier to put in with the motor. If price is a problem, I have had good success with Flowtechs fitting like they should in everything. Paint sucks, and welding could be much better, but they fit and get the job done.

Later
Steve