307 Head Question

[84calais]

I have a 307 out of an 86 custom cruiser and a 307 out of an 84 calias. The 84 engine has 5a heads. The 86 engine has 7a heads. my question is could i put the 5a heads on the 86 model block, and if so what would i have to change.

 

[88ss408]

as far as i know the heads will bolt up no problem. you may need custom lenght push rod tho. some olds guy from here will be able to tell ya for sure.

 

[joe_padavano]

I have a 307 out of an 86 custom cruiser and a 307 out of an 84 calias. The 84 engine has 5a heads. The 86 engine has 7a heads. my question is could i put the 5a heads on the 86 model block, and if so what would i have to change.

The heads bolt on, but you want to use the intake and exhaust manifolds that go with the 5A heads. The late 80s A5 intake and tubular exhaust manifolds have much smaller ports to match the 7A heads. The A4 intake and cast exhaust manifolds on the early 307s flow better.

 

[jk383400]

I have a 307 out of an 86 custom cruiser and a 307 out of an 84 calias. The 84 engine has 5a heads. The 86 engine has 7a heads. my question is could i put the 5a heads on the 86 model block, and if so what would i have to change.

The heads bolt on, but you want to use the intake and exhaust manifolds that go with the 5A heads. The late 80s A5 intake and tubular exhaust manifolds have much smaller ports to match the 7A heads. The A4 intake and cast exhaust manifolds on the early 307s flow better.

I almost went in this direction 2 yrs ago, i changed my mind & managed to get back the $250 I spent for these heads, intake & exh manifolds & even dual snork aircleaner.. , i figured what was the point? to get perhaps another 1500-2000 rpm out of the motor ? This change would have perhaps brought the same kind of excitement my stock H.O. 305 I used to have in my Monte ? .. I like the real low end torque that the 7A car has & it'a a great reliable cruiser..