What is a good stall to go with a 3:23 Sure Grip?

In my humble opinion.....
The more motor (displacement) you have with 3.23s, the less stall you need. With a 360, I'd try for~2500. With a 440, 2200 might be fine.
On the other hand, the more cam duration you have, the more stall (and gear!) you need.
Just don't buy the cheapest converter you can find.