Usually - the bell bolts to the case on a case fill C4. Those would use a 164T flex plate on a 351W, etc. The case fill units should bolt to the pump. That may not be universal, Ford liked to make design changes as we all know LOL. But the early 70s cases I use follow that logic. I think a lot of C4s (C5s?) after 1975 or so were primarily pan fill. The two "big block" C5s I have the came from behind 1978 era 351Ms using a 429/460 bell pattern and the bell bolts to the case with a pan fill dip stick.
>Chris, you prefer case fill over pan fill because of fitment or ??
I like the smaller 157T bells. At least around the bell area, it's a tighter package. Little easier fitting headers into a Falcon/Fairlane chassis with a small bell. Requires switching to a PMGR start on something like a 351C block because it tucks the starter in closer to the pan rail, but those PMGR units are so good that should be a "just do" kind of thing.
Even the dragster uses a 157T flex and a JW 157 adapter bell from a W pattern to a Powerglide.
