If you are going to run a blower, you need the compression down around 8 or 8.5:1. 305 heads do choke down a 350 and not allow it to breath correctly. Just because others run them doesn't make it the right way to go. There's lots of good chebbie heads around, why waste time with something that won't allow the engine to breath good??? Especially if you are going to run a blower than the runners really need a lot of CFM and big valves to get the compressed air through the heads and into the cylinder.

A 292 does make a lot of torque and is a great truck motor.