Pulley System

Dan the man said
The truck motor mount bracket, does it matter if it's from a small block or a big block? The thick motor mount from a/6 duster does it matter what year?

A big block bracket will not fit a small block.
Use the slant 6 biscuit from the year K frame you have. Or better yet, use the 2710 ('90ish Cummins) biscuit, same thickness as the slant isolator, but has interlocks on it- no need for a torque strap.