all right i am getting a holley street dominator intake for a resnable price to put on my 350. i know the center bolt holes are at a different angle on the pre 86 blocks. the intake is for the older style heads. 1st question is what do i need to use to elongate the holes to make them work? 2nd what way do i need to go. toward the center of the intake or to the edge? any help will be greatfull.

 

You would have to open them upward and outward about 18°, then provide a flat (bearing) surface for the bolt to shoulder on.

 

thanks.