[TheGhost]

The "double hump" heads as rule of thumb are 64 CC heads. So, you would be in the same place as the Vortec heads.

Just some thoughts...

A camshaft will affect cylinder pressure not compression ratio.

Static compression ratio is based on fixed mechanical features of the engine:
Cylinder Bore diameter, compression height of piston, combustion chamber size, head gasket thickness, etc..

A short duration high lift cam will build more cylinder pressure than a high lift long duration cam.

A camshaft can effect dynamic compression ratio(cylinder pressure).

So, when you put a bigger cam in an engine, you aren't really giving up compression. You may have lower cranking pressure, and less low speed performance, but sooner or later the extra duration will help get more air into the engine than you would have ever gotten with a smaller cam. Eventually both cylinder pressure and power will go up even if the actual static compression ratio stayed the same.

There is one side efect to this though...detonation, which is based in part on cylinder pressure and engine speed (or the amount of time the fuel has to detonate). The faster an engine is spinning, the more likely there will be a leaner mixture, and the less time it has to detonate. Because of this, an engine with lets say 9:1 compression and a very early intake valve closing may be able to trap most of it's intake charge in the cylinder at a fairly low speed. Since the engine is spinning at a low speed, it won't be able to make as much pressure before the fuel detonates. The result would be an engine that detonates at low speeds and lacks high speed performance because the cam is too short. An engine with the same compression and a later intake closing event will trap less air in the cylinder at low speeds, and wont be as prone to detonation at low speeds. At higher speeds, the engine will intake more air and make more pressure, but since the engine is spinning faster, the fuel has less time to detonate, and detonation is avoided despite there being more pressure.

All this to say...make sure you really take some time to consider your camshaft choice as it relates to static compression and not place to much focus on any one component. Everything has to work together. Otherwise you end up with and engine that sounds great at idle, but doesn't really live up to it's potential. A rough idle can be accomplished by pulling off a vacuum line... :-)