There is a problem with using the FMS base in conjunction with a (Mopar) stock top. The choke horn comes very close to the lid and it's really restrictive. Due to the contour of the lid, you end up with about a 3/4" clearance from lid to base at the narrowest point.

If you run a carb without a choke horn, you'd probably be okay, but the 3/4" clearance is still pretty tight.