I'm not saying its going to starve for air. Its just physically impossible to cram that much air down the ports. It not going to starve at all, but more air means bigger explosion and more power in the combustion chamber. The ONLY advantage to 305 heads is higher compression and thats really not big of a deal when the best pump gas you can get is 91 octane. You can compesate with a big cam with valve overlap to bring the dynmaic compression ratio down and run on 87-91 octane just fine. But, just saying don't expect the big performance. Think about the purpose of a big cam, and is the 305 head really doing it justice? IMO, its the making of a motor that SOUNDS mean as hell but has no go. Then the guy next to you with a mild RV cam and a set of vortecs idling almost as smooth as can be sounding stock is gonna give you a spankin and embarass the hell outta you. Why? Becasue he is cramming more into the cylinder with better breathing heads. Head ports are always the bottleneck of air flow. This is why selecting a good head casting and maybe even work it over a bit will run much better.
ok don't want no spanking so i stay from that combo...wants the normal compression on a stock 350? Is there a way to tell by how much compression your getting what kinda of pistons you got? all things being equal...does a cam or boring raise compression?
The later 350's are about 8.5 or 9 to 1 compression stock. That's using a dish piston and 76cc heads. Smaller combustion chamber heads raise compression, flat tops without a dish in the piston raises compression, longer stroke raises compression, boring will raise it a tad, milling the head will raise it. There is static compression ratio which is what we talk about when we say 9 to 1 or, 10 to 1 pistons etc. That's what you mathematically have by calcutating bore x stroke, head cc volume, head gasket type or whatever. Then there is dynamic compression ratio which is our ACTUAL compression ratio. With a big cam, your intake valve isn't always fully closed when the piston starts coming up on compression stroke, so you lose all that compression til the intake valve is fully closed. So if you have a static compression ratio of 10:1, but a big cam, your actual compression ratio could be 9:1 for the lost compression. This is why if you have a high compression motor, with a big cam to compensate you can still run pump gas. I'm not the expert in explaining this stuff, so you might want to do some searches for things like dynamic compression ratio and see what you find out.