The easiest way is if you know the manufacturer call
them with the number on the conv... also if you know
the real torque of the engine it was behind you can
calculate the P factor for that set up then if you
kow the new torque you can figure that P factor to
come up with the new stall... I'm running a 5000 stall
8" in a 518 trans with a standard valve body with
a shift kit... that part inst any problem but the
518 has OD so I might run into a temp issue when
in OD if I'm not rolling fast enough... I'll find out