I have a 4 bolt main years 87-94. I was looking at a new intake and heads and they keep saying up to 86. If im building this from the crank up are those years still applicable? If so what changed between 86-87?

 

The bolt pattern for intakes to heads changed from 86-87.

 

So If i bought an 86 intake with 86 heads would they bolt up to an 87-94 block?

 

Yup; all heads bolt to all blocks (up until the LT1).

All that happened in 87 was, they changed the angle of the center 2 bolts on each side, where the intake bolts to the heads; and went from perimeter-bolt valve covers to center-bolt ones.

They changed the intake bolt pattern again for Vortec heads, in 96. But those heads still bolt to all blocks back to 55.

 

Thanks guys. Thats the best news ive heard since i got the ol third gen.