what is the difference between 86 and older heads, 87-95 heads, and vortec heads? i know that some haeds have a 23 degree plug angle or something but i heard that a intake for86 and older engines wont fit a centerbolt head or vortec and centerbolts are different than vortec why???

 

i guess this must be a hard question?

 

Idon't know why... Just the way it is...

 

the ones pre 87 had bolts on the outside instead of centerbolts. just a slightly different head for a slightly different block. as far as the vortecs theyre machined slightly smaller for higher combustion. same heads just built to maximize oem power i believe. my friend put vortec heads on his that didnt have vortec before and no problems.

 

i know about the valve cover bolts i thought the angle of the head where the intake sits might of been different or intake or exhaust ports being slightly different but thanks