The 200-4R is a bolt on unit. and has better ratios than the 700-R4. 200-4R 700R4 1st--2.76 1st- 3.05 OD - .67 OD- .72
700R4 in BBB Joe, I'm aware the 200-R4 offer better gear ratios and I would prefer it but the 700R4 is free and recently rebuilt. Hopefully it will be strong enough for a mostly street driven Buick.