Mopar A833 iron, 63 B or C Body questions ?

Can u swap guts with 1976 833 aluminum OD
Trans ?
Don't want a 3.09 first gear

Yes, but I would use the 64-65 main case. It is stronger, uses the correct for A body small front bearing retainer, and the tolerances are tighter. The O/D main shaft is different than the A body std main shaft, so you can not use the 64-65 gears on the O/D main shaft.