Chryco was the guy who helped me put my first OD tranny behind a B/RB engine, about 6 or 7 years ago, and ever since then I use them exclusively. I've put 'em in Mopar A, B, and E bodies, and one into my Model A when it was running a 383 Mopar with 4.88 rear gears. Wild!!
Except for the gear sets and some small parts internally, ALL 23 spline A-833 transmissions are the same from '66 to '88. They even put the A-833 in some Chevy trucks and vans, but those use a different main case than the Mopar units.
The one main difference is the input bearing retainer will need to be turned down a bit on a lathe, any machine shop should be able to handle that. I just use my buddy's lathe, it's pretty simple.
The only Chrysler four speed I've ever hurt was an OEM cast iron 23 spline unit from a '68 Charger 383 4 barrel car, and even then it was only the synchro for first (I think). I've never destroyed a later model unit. My buddy with a 489 cube stroked 383 in a '66 Belvedere with 3.91s uses one, along with an aluminum flywheel, and that thing has assloads of torque.
As far as aluminum flywheels go, I love those too. Feels a little less "torquey" off the line, but the way it revs up incredibly fast it well worth it.
