Slant 6 with 200r4?
Yep...GN's got the best ones, though the Monte Carlo, 4-4-2,and Hurst-Olds got upgraded ones. So did some B-bodies (seems to be wagons and some Caddys). Also, the later the TH-200-4R, the better it is as a core! (Mine came from, IIRC, a 1986 Cutlass.)