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Old 10-15-2021, 12:16 AM
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68gtoMN 68gtoMN is offline
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Join Date: Nov 2005
Location: Minneapolis Area
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Originally Posted by Carousel72TRed View Post
Does anybody know what the torque converter stall/lockup speed was on a stock TH 400 transmission? I've been told varying stall stall speeds from 1200-1800 rpm . My car came with factory AC so I believe the rear end ratio in my car is 3.23. I've also heard the peak torque rpm on a Pontiac 400 is around 2300 rpm so the best torque converter for this would be one that is around 2000-2400 rpm? Of course it may not do much good getting an aftermarket 2000-2400 rpm stall speed torque converter unless you have a limited slip or positraction rear end.

Carousel72TRed
Pontiac engines produce prodigious torque low in the rev range, but peak torque for GTO 400 (350 HP in 1969) is approximately 3000 rpm.

From Revmaxconverters.com: "In general, the desired stall speed should be 500-700 RPM below the engine RPM at peak torque. This ensures a margin for application for the torque converter to take off. You don’t want to have to floor your gas pedal and wait a few seconds for your vehicle to move. "

Higher stall speeds mean higher heat, faster trans fluid breakdown, likely higher engine operating temps and drive line stress. Just keep your wits about you with your decision.

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