curious to know if i could try to us an aluminum 350 head with the smaller chambers and 1.94 valves on a 305. will the valves clear the smaller bore? i know world makes an iron 305 head, but i want the lighter aluminum.

 

yah it would work fine, just use 350 head gaskets with the heads.

 

Your effective compression will be lower, even though the static compression will be about the same as with the iron 305 heads.

Basic bowl work/pocket porting would probably make up for the loss in compression.

 

would the compression be lower even with 58cc chambers?

 

As I said:
Aluminum transfers heat more rapidly than iron. Heat = energy, so the energy lost from heat transfer would mean less energy to drive the piston down. So, to make up the lost energy, the static compression is raised to regain the power.

An iron-headed L98 has 64cc chambers for a 9.3:1 static compression ratio. The same L98 with aluminum heads has 58cc chambers for 10:1 static compression ratio. Same power, no problems with pinging, etc., etc., etc.

For a 305 to have the same power potential (all other things being equal) with aluminum heads as it does with iron heads, you need a higher compression ratio with the aluminum heads than you do with the cast iron heads.