if the t96/t14 and sr4/t4/t5 do share upper bolts that makes things easier, but according to advance adapters they're completely different. the old pattern is about 6.25" * 5.25"; the new is 7.92" between the upper holes, 6.32" between the lower, and 6.27" top-to-bottom.
I just went out and measured my pre-72 and post-71 bells. These are six cylinder parts.
Old bell: T96 to 232 New bell: T14 to 232
My "late" bell is double-drilled though, it'll take the T14 or the T96 transmission, though the center hole is 4.75" on the late bell and about 4.25" on the early.
THe early bell is overall smaller, by 1 - 2" overall diameter (it's of course not exactly round).