She's Real Fine, My 409....

[mrbudge]

When I went to school a long time ago the first question in an automatic transmission test was how much does a torque convertor multiply torque. The correct answer was 2x, I remember that because I got it wrong. I have never tested a torque convertor to find out for myself.

[jimmy57]

From one source: Typical stall torque multiplication ratios range from 1.8:1 to 2.5:1 for most automotive applications (although multi-element designs as used in the Buick Dynaflow and Chevrolet Turboglide could produce more).

 

Torque converter multiplication factors may have a median value of 2:1 but they are not all 2:1.

[Jim Warman]

The small V-8 answer is the bellhousing flange - 5 bolt on the early blocks - built to fit into the compact cars of the day I assume - versus the more common 6 bolt flange of the later engines. FWIW, all the 5 bolt engines came from the factory with a generator (including the 64.5 Mustang I had).

 

For torque converters... more multiplication = more heat. Important considerations are the vehicle and engine combination... These factors will have an effect on whether a torque converter is "loose" or "tight" (has a higher or lower stall speed)