Torque Converter

Hi guys My name is Mike. My son and I were lucky enough 4 yrs ago to find a 69 Fastback M Code Cuda. Through research we know the entire history and owners that owned the car previously. Most of its life it was drag races. My son who was 12 at the time paid for the car with his own money. Only thing not original is the engine yet we do know the man who has it here in our city but won’t part with it. We are getting down to the wire as he wants
To take it to prom next year. The issue we are having is the rearend was ordered with 3.23 gearing as it was before March of 69 when they all went to the 3.91. I am wondering what the original stall speed would have been with the 3.91 gears? I called Hughes converters. Gave them the Thumper Cam specs, rear gear ratio, tire height and weight of the car. The tech told
Me it need the 3000 stall, part number 24-30-440BAL. That’s if we had the 3.91
Gears. Seeing we already put 1200 in the original rear and and didn’t change the gears(we should have) the tech said that the Thumper Cam will not work
With that high of a heat and it will need the 3.91 so as not to cause the trans to heat up and it would be a dog on the streets. So for now do I buy the 3000 stall or go with something like a 2200-2500? Any input would be fantastic!Thanks guys! Pics were the day we picked it up. As of now we have not done an original look to the engine.
We are hoping to buy the original one from the doctor who has it in his 68 Charger.

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