i know an olds 307 and olds 350 parts are interchangeable i was wondering will 350 heads and intake work on a 307 block and if so will i gain anything or just a waste

307 is an 1985

i know the exhaust manifolds are the same from 307 to 403
any help is greatly aprisiated

 

An 85 307 could be either a flat tappet cam motor with 5A heads or a roller cam motor with 7A heads. The improvement from the 350 heads depends on which ones those are. 350 heads did come in different chamber sizes, so CR may or may not be increased. Also, any 350 heads from 1968-76 will need to have the head bolt holes and dowel pin holes opened up to fit on a 1977-up block. 350 motors built from 1977-1980 already have the larger holes. Finally, if you have a roller cam 307 with the A5 intake, you will need a different intake due to the tiny ports on that one.