What problems will arise

[ksjh1316]

Can't seem to find a decent 350 from a 67-72 in this part of the world but i did find one that was just rebuilt 20k ago out of a 81 GMC 1/2 ton. This motor should be turn key will all accesories and brackets and exaust manafolds.

The question I will have to use 80's exaust or is there any difference and will I need a new wiring harness for the front as I still have my 292 harness in the vehicle, and lastly can I use the 67-72 motor mounts or do I have to fit the 81 mounts into my frame.

Thanks for the help and any other problems I may run into.