Okay.. My issue is I wanted to replace the stock converter in my U code Challenger with a sightly looser one. So after doing some searching I bought a 11" TCI. From what I remember the 383 and the 440 727's received the 11.75" or 12 inch converters??? I do remember this topic from once before, and I think it was about stall speeds and such????? So, my issue is... the converter mounts don't line up with my flexplate holes? I know I'm gonna need a different flexplate, but the question is from what? Hoping John K. will chime in and help me! Lol... Once I get the tranny pulled away from the engine again I'll do some comparisons wth the old one since I wasn't smart enough to do that to begin with... I just would have thought the ring gear and converter mountng holes would've been the same and just the converter diameter would change??? Thinking maybe the one I have is incorrect for me? TIA

There is two mounting patterns for the converters, small and big. Sounds like you went from one size to the other. I am sure you already noted as well that the bolts and mounts only line up one way, that is the converter holes and flex plate only line up in one of 4 positions, eh? Also, there can be different size bolts for the different converters, I believe going from 3/8, 7/16, to 1/2 inch as well. Good luck!

If you are not concerned with the flexplate being of the Mopar design, I used a B&M flexplate in my 66 because it came with both bolt patterns and bolt sizes.

Was the dia of the 4 plate holes too small (904 plate) & wouldn't fit the larger "circle" of the bolt hole pads on the 727 converter? & as you know it has to be clocked to the right position for all 4 holes to line up (Not being patronizing just checking). What's going on?

The issue is they are about half an inch shy of meeting the holes in the flexplate all the way around... That's why I was wondering if the diameter was an issue? What I mean is if I measured a half inch directly above my holes and drilled holes it looks like it would bolt up? Like I said earlier they are on a smaller diameter measurement. I'd like to keep my stock flexplate... I'm wondering if I even have the right converter. I'll post more when I get it out to compare.

The 10 3/4" (11") converter uses a flexplate with a 10" bolt circle, the 11 3/4" (12") uses a flexplate with a 11 1/8" bolt circle.

The 440 used the larger converter, HP 383 used the smaller converter. Redrilling the larger flexplate for the smaller converter is doable but I'd get the correct one.

Any ideas where I can get one???

Mancini has new

http://chucker54.stores.yahoo.net/flexplat516b.html

Lots of used ones on e-bay