howziit guys!
if we're working with sbc 350's, i'd go for the block which would need less machine work.
for your intent and purpose, you don't NEED a 4-bolt block.
JMO, it would be nice, if you could have those 305 heads flow-rated.
you still need to take into consideration...a cam, compression ratio, intake, carb, convertor, gears, truck usage, rpm range, etc.
stock 305 heads have 58cc, which would raise compression about a half-point....unless more cc's were added with the custom headwork.
i GUESS you could try those 305 heads. i'd make sure cr wasn't more than 9-9.5:1.
