I found a broken motor mount on the driver side if I get some $50 polyurethane Energy Suspension mounts can I reuse them if i drop in a power full stroked 350 and reuse the mounts?
Or should I drop in 2 sets of rubber ones( one now and another set later on with the new engine)?
The rubber mount is totaly gone.

 

I dont see why you cant reuse the poly ones. Hell I reused the rubber ones after I had my engine out.

 

Sure you can. I've got the ES mounts on my car. They don't wear out and sag like rubber - and I seriously doubt they will break

 

I just started redoing mine and am putting in Prothane inserts into the original housing. Basically all you have to to do is grind down the rivets on either end and then drill out what left in the center a bit. The Prothane inserts are very nice pieces.