518...46RH
builds like a 727...with od in the tailhousing.
bolts right up to the small block.
get the year with three pin connector if you want lock-up tq, 2 pin just od.
Theres a 904 version too...just dont recall the #.
I have a 518 (ok, 3 of them:D) thats going behind a warm 360 in my Aspen...