74 Dart 360 Sport

Lot of clunks and noise from 727A. I think it's letting me know it does not approve lol. Has anyone used the AX41 automatic from SST? Turn key conversion to a 4 speed auto 4l60 is similar but I want something more simple not all custom using old stuff building a kit myself.
TREMEC TKX, TREMEC Magnum & SST A41 Conversion Kits for 1967-1976 Mopar A-Body: Dart, Valiant, Barracuda, Duster, & Scamp
I have a customer who has thier five speed stick shift and it leaked after less than five hundred miles... paid to ship it back... bought a second one as well and it's leaking after the same amount of miles...