The most precise way is on an engine dyno. You want one that stalls a couple of hundred rpm below your peak torque.
Chosing a converter stall speed should be left up to the manufacturer. Call up any of them. They'll want to know all sorts of information about your car and engine then they'll suggest the proper converter and stall speed for your combination. Not all converters are built the same and a converter that stalls at a specific speed on your engine will stall at a different speed on a different engine.
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Follow my racing progress on
Stephen's racing page
and check out the
race car 
87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block
Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546
Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the
Calgary Drag Racing Association
87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley
