Help ID tranny

I just picked up a 73 360/4 speed setup that was soposidly in a 71 Dart, and I was wondering it someone can ID it for me. Its an Iron case 833 with ...

C-99386 on the cover
C-99129 on the side of the case
C-99126-1 on the tail shaft

I have an aluminum OD A833 in my Duster now and I dont know if this is an iron cased OD or a regular 4 speed.

Can anyone tell me what I have? And what would be the better trans to use? Its a mild 360 bored .030 with what I think are low comp, 4 valve relief cast or hyper pistons, J heads with 2.02 stainless valves, and adjustable rockers with dual plane intake, holley 650, and headers with a Comp xe 274 cam. All in a Duster with 3.91 rear and 28" tires.


Any help would be appriciated

Butch