steering rack and pinion rubs underneath!?!?!?

Couple things you can do depending on how much interference you have between the steering shaft and likely one of the header tubes - happened to me with a 351 swap and simple swap shorties.

You can loosen the motor mounts and jack it up just a
tad and put a thick flat washer or two or three between
the mount bracket and the crossmember.

I had to get a set of the poly offset rack bushings and
use them to move the rack just a tad to the side instead
of down like usual. That moved the shaft about 1/8" or a hair less to the left, JUST enuf to clear the header tube. You then need to readjust your tie rods to recenter your steering wheel and then get it aligned.