What flex plate used?

[b5blue]

440HP's used a stock flex plate? 

[John_Kunkel]

All factory engines used a "stock" flex plate...which one depends on the year. All 440HP's prior to '73 used the 11 3/4" (12") converter which takes a different flex plate than the 10 3/4" (11") converter used '73 and later.

[b5blue]

Thanks! I just got a PRW SFI rated one for my forged crank 440 to 145K Mopar torque converter. Quite a beefy part compared to stock!