Why put a Chevy trans in a mopar........ He has a 4 speed 340 car, not exactly found everywhere. And I'm guessing he likes the 833.
I agree!! A 4 speed car is GREAT!! I put a Chevy trans in my car because it was survivor and didn't want to "cut it up" to install a Mopar trans just to get overdrive.
Assuming you have a 8.75 rear, not that bad at all, you can get an assembled center section and swap it in an afternoon fairly quick. plus you could sell the 3.91 center as is and pay for the swap for a 3.23 center section. Youre looking at anywhere from 50 bucks on up to 4-5 hundred bucks for the center sections depending on casting number, sure grip or open and ratio.