I thought I read they did but I wanted to make sure.Are the truck trannies cast iron or aluminum and are they strong enough for a big block?

Yes, they will fit B and E bodies. Some are fully aluminum, some fully cast iron, and some a bit of both. I would be unlikely to put one behind a healthy big block.

Yes they'll fit behind a B/E body however you have to deal with the larger bearing retainer on the o/d trans. Some say the o/d trans is plenty strong if you at least take care of the floating shaft issue. On the truck/van o/d 833, the shifter mounting boss for the e body/71 B body console shifter is there but the holes in it are not drilled.

It is going into a 68 b body.Do they use the same shifter pattern as the trucks?Its going behind a mild big block.Would the truck shifter fit the b body?

You can machine the OD transmission's bearing retainer to fit a '68 and newer BB bell housing.

The truck shift mechanism works in A and B-bodies, but you must change the rods, shift handle and side mounting bracket.