does anybody know if aftermarket heads for a 350 will work on a 305 as long as valve size and lift are kept within the limits for a 305? my main concern has been the water jackets. thanks

 

Water jackets are the same.

Valve size is not an issue, until the valves get large enough that they overhange the 305's dinky bore. Lift is NEVER an issue except as above. Of course, since the HIGH FLOW area of the intake valve happens to be along the are where the valve will come close to the bore (bore shrouding), the flow with a larger valve can actually end up LESS than the flow with the right size valve.

The REAL problem (besides it just being a 305 generally) is that the chambers are usually too large, and you'll ned up with no compression.

 

Any good aftermarket 350 head will have 2.02 or 2.05 intake valves and 1.6 exhaust valves. I was told these would hit the 305s dinky bore -- but have never mocked up to try. Sofa do you know if they will?

 

Not all heads are designed exactly the same. The valves aren't always in the exact same place. Plus, there's a certain tolerance in a block as to where the head dowels are located on the deck, so even THE SAME heads might fit 2 different blocks differently.

Most of the time, 2.02"s won't hit; some will. Most of the time, 2.05"s will. Reason being, the largest valves you can put into a head with the stock guide spacing, is 2.02"/1.6". To get larger ones in, they HAVE TO BE moved farther apart. Which of course locates them closer to the cyl walls.

But if they're THAT close already, how much flow can possibly occur around the edge that's RIGHT NEXT TO the cyl wall? Even if they don't actually self-destruct, they're self-defeating. A smaller valve with more clearance will run better.

 

The 350 L-98 corvette ZZ4 aluminum heads with 58cc chambers and 1.94x 1.50" valves work great on a 305.

Any head with a 2.02 valve is a bad choice for a 305.

 

is that true? i just happen to have a set, and am getting a rebuilt 305...i was thinking on putting a big cam in it anyways.