Not a bad swap, but as said earlier some of the parts can be a pain to get. The pulley issue can be solved by using the pulleys from a small block short water pump. Will need different fuel pump and water pump. The oil pressure line is different, the trans mount moves if you use the th400, the shifter linkage is different, and in different locale, drive shaft length will change and front yoke if th400. Same distributer. Mounts will be the toughest part to obtain. 68-71 stands still available from GM $35, but the pads are $75 per side, 72 pads are $14 per side but stands going for $85 and up depending on shape they are in. Then the exhaust will have to be changed- either headers or manifolds (manifolds can be difficult to locate w/o smog holes). The brackets are available- many of the same things were used on 67- down chevelles and big cars, biscayne and impalas. If you are set on big block you are going o throw some money down, if you have access to SB400 stay with small block and throw the extra money at it.... they can go real fast
