In one of my mustangs (79, 80, 86) I swapped the 1 bbl for a 2bbl (on the 4 banger). Had to go to the junk yard and get the manifold spacer, a nifty between the manifold and carb aluminum piece which has the EGR plumbing and bolts (allen head) to the manifold allowing Ford to use the same intake for both carbs. You might want to check to see if they did that also for the 6. If so, that helps with the clearance issue a lot. Just my 2.5cents (due to inflation) worth.