318 to 360 conversion engine mounts needed

I forget what the difference was between the 318 mount and the 360 one. My son has a 72 C body wagon project that has it's original 360 short block in but has been sitting with no heads on it for who knows how many years before he got the car.

. Can only move crank to move pistons ~1/4" in their bores even with a "cheater" pipe, bores are rusty.
Yes we have been soaking them

We didn't get any heads, or manifolds, with the car.
He just wants to drop something into it to get it mobile under its own power "for now" so he bought back one of my old trucks from my cousin for the 318 that's in it, because he knows exactly what I put into that engine when I had it It did a great job in that truck, which is an 83, 3/4 ton. He wants to put my old 318 into that body. I know about the balance difference, between 318-360.
I have a couple of 360 magnums here, I believe his plan is to eventually build up one of those, for this Fury wagon. Or possibly the original short block, as a basis for a new engine /eventually.
What is needed for the driver side motor mount to drop a 318 in where a 360 was? .
We don't want to destroy the original 360 one so we can use it on the new motor once built up.