From my research, HP/torque, car weight, and gears all affect converter stall.
Looking for rule of thumb on what a given converter will stall when the parameters are changed.
Given the following, correct me if wrong:
- More HP/torque will increase stall speed
- Lower gears, such as a 2.73 or 3.08 gear, will increases stall
- Heavier the vehicle, the higher it will push the stall of the converter

My goal is to buy a stock rebuilt converter, $150, not interested in spending $600 or more on a "custom" converter.

Assuming gearing is a wash, my HP is up (75-100%), but weight is down (10%)
Double HP won't double the stall, but is there a rule of thumb?
Given the numbers below, I'm leaning towards the 1350 stall, and thinking/hoping it works out to ~ 2000-2500.

70 Challenger, 5.7, 518 OD/LU, 3.73 gears. Mainly a cruiser, not out for max performance
HP/Torque = 400/400
Weight = ~3700

Converter choices:
95 B3500 Van, 318
HP/Torque = 230/300
Weight = 4000
Stall 2100-2400

78 Charger, 318
HP/Torque = 140/150
Weight = 4000
High Stall 1700
Low Stall 1350