Anyone familiar with rear mount for Trubo 400.

Need one with a front to back offset of about 1 - 1.5 inches.

Two bolts to the top to the tranny and one on the bottom to the crossmember.

Anybody got a part number?

Apparently came on late 80's - 91 pickup with turbo 400, but the local parts guys can't figure it out.

I have never heard of a mount like that and I have been working on Chevy trucks since the 70's. If one exists and you find it IMO the mount would be weak because the load would not be inline with the crossmember. The best way is to move the crossmember back so that it is directly under the mount, most frames can be easily drilled if the correct holes are not present.