[Rory McNeil]

The factory high performance Ford Holleys with the center hung float bowls have threaded inlets on the primary bowl only. They had a thread in fuel filter on the drivers side, with a small transfer tube between the primary & secondary bowls. I`m not sure if you could use 2 of the Ford primary bowls for both, since the the sight plug hole is often at a different level between the pri & sec sides. Also, most of the Ford Holleys have a hole in the top of the primary float bowl, for use with a bowl vent lever setup. Not really something I would want on a rear bowl, due to potential fuel leakage on launch. Holley 4500 Dominators do have float bowls that are threaded on both sides, and I think they will work on a 4150/4160 carb. You could look into that.