I have an 81 scrambler with the factory 258 and sr4/dana 300. I have bought a sbc and sm465. I am trying to get all the info together before I swap, because it is my daily driver. What I want to know is when I do the engine/ tranny swap and mount the dana 300 will I need to lenthen my rear drive shaft? I know the 465 is the same length as the sr4, but when I mount the sbc will it sit further ahead or will I be able to to mount to the same length as the 258? Please help.

Lift height?

There's alot of variables here. You're going to have to put in the drivetrain, then measure to see what you need in terms of shafts.

the bolt in engine swap mounts allow you to move the motor forward or back an inch and also up or down an inch from the stock mounting locations. and it also has the stock location as an option too.

The lift height is 1.5 inches from a shackle lift.