Why do you want to use domed pistons? Based on many years of reading Hot Rod and discussions with engine builders, flat tops are better, especially with more recent cylinder head designs such as the Vortecs. These heads attempt to induce swirl or tumble to the mixture to provide faster combustion. Piston domes impede flame travel across the cylinder because the flame has to go over and around the dome.
The reason I need high compression is that I'll be using the heads on a circle track car motor. The cam requires high compression on the order of 11:1 to 12:1. I'm impressed with the flow on these heads and would really like to try them.
These heads are not straight across between the valves at the quench area, I suspect this would cause some interference with the piston dome. This 'kidney' shaped area is supposed to be part of the improved design that makes the heads work so well.
Domed pistons will not work unless made for the vortec chamber. Shaving the heads may help your compression some, but the real question is what exactly are your intentions. On a strong street motor they would be great but on a high RPM race motor I think you could do better. They have 1.94/1.50 valves which are small for high revs. The stock springs and press-in studs may not work well either. For a little more you could get world sportsman II heads, or good aluminum heads and not have to use a different intake(less options to choose from with vortecs). I have a set on my 81 suburban and I'm pleased with them but wouldn't recommend them for over 6500 RPM. Under this RPM I wouldn't think you would need much more than 10:1 compression. Flat top pistons with the 64cc chambers should run about 9.5:1 or a little more without cutting the heads.
I would also use a forged flat top piston, 0 decked, and mill the heads accordingly. With stock 64cc chambers and 0 decked flat tops, you are already at 10.25-10.5 to 1. You'll definately want to change the springs as the stockers are pretty weak, and pay close attention to the retainer to guide clearance.
375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
I have vortech's on my 350 with a set of .125 domes and haven't had any problems I'm also running fel-pro 1094's which bump it up to about 11.4:1 i still run 91 but have to keep the timing back a little.
[This message has been edited by street-racer-n-okc (edited 02-26-2002).]