I have a 1968 B body, with a 440 i just finished. It has a Comp Cams XE275Hl .525 in/ex with 231 and 237* at.050.. About 10.50 compression with decent ported heads, street dominator and holley 750 DP and 3.55 gear. The power band i believe is 2000 to 6500 or so. My question is what is the bare minimum stall needed just to get it to idle in gear decently.

Any stock type converter will meet your needs, any of the B,RB, or even one out of any 318 or 340 727 car built before will work fine fou 1972, all production 340 motoorsbecame externally balanced starting in 1972.

The factory 11" (10 3/4") should fit your needs; you'll need to change the flexplate to one with the 10" bolt circle.

I didn't like the factory vert with my .509 cam with 452 heads because it really lugged it down in gear low rpm.

Initial timing aka spark lead at idle will have a much greater effect on idle quality in gear
than torque converter selection.

The Max Wedges had the tightest converter ever installed on a 727 and they idled in gear just fine.

Of course. But the OP does not have a 509 cam.

Do you know how big the M.W. cam where, especially in the 1964 motors?
They where both quite a bit bigger than the 509 are!

Im running the same cam and a similar setup with a convertor that stalls 2800-3000. Car runs and idles great. I do have 3:91 gears...car launches great!

No he has a .525 cam.

Right. But lift has nothing to do with it.

His cam has a bunch less seat and 0.050" timing, and a bunch less overlap, which is what matters in this discussion.

My 0.630" lift cam idles fine with my stock converter, as an example how lift does not really pertinent in this discussion.