B/C Body 4 speed into an A-body.

You'll have a few options if you have your heart set on that transmission, to install "as is" you'll have to hack the living daylights out of the trans cross member and you'll wind up with the shifter handle somewhere up in the ash tray, the shifter mechanism and the cross member will be trying to occupy the same space.

Another option to use the transmission "as is" you'll have to fab a bracket to mount the shifter in the A body location, this will still require some hacking at the tranny cross member as the fabbed mounting bracket and the cross member will be trying to occupy the same space, but the shifter will be in a usable location.

Yet another option is to change the tail shaft on that tranny to the later B/E body style and then fab a bracket to mount the shifter in the A body location but that will either require a big dent in the cross member to clear the forward shifter mounting bosses or partial removal of the bosses for clearance.

The easiest thing to do is pass on that transmission and find an A body unit, this will simply bolt in