350 heads on a 305 doesn't make it a 327 the bore and stroke of the motor is what makes cubic inches 350 if closed will ive more compression and more power. If I remeber a 350 has a 4.00 bore and 6.00 inch stroke and a 305 has a 3.875 bore or something whatever got one for sale cal me 925-382-1058
The combustion chamber in the head is what does the trick for the motor.. I was half a sleep, may be i got it back wards 302 heads on a 350 block. I'll double check when I'm a little more awake..
![Head Scratch :headscratch:](https://board.marlincrawler.com/Smileys/marlin/headscratch.gif)