Both the 787s and the 964s are 216-application. It would be good to figure out if both were setup (both originally and current state) the same in terms of venturi size, main jet size, and metering rod. Might keep you from chasing your tail on tuning if there are internal differences that need to be resolved.
I have some literature stashed with those kinds of specs on the 2100, 2101, and 3211 (235 carbs). I don’t have any on the 216 carbs.
I bet someone here does, however.
