Probably been covered a lot before but I cant find a straight answer. How can you tell apart a 305 and 350 vortec head? They hace the same casting numbers. I was thinking the CC is smaller on a 305 and what size would that be so I can measure them or if the intake valves are different sizes? Or any other differencesso I can find out if I have a set of 305 or 350 vortrc heads. I have the 062 casting heads

 

350 casting numbers = 906 or 062

305 casting numbers = something else

 

305 Vortec heads have casting numbers 12552520 & 12558059.
Here's a link to an article with a little info:
http://www.hotrodders.com/forum/305-...tec-93204.html

 

If you chanfer(sp) the bores it helps un-shroud larger intake valves on the 305 bore size.

 

He has 062; 350 heads.

None of the 305 stuff really applies anyway.