I was getting some substantial hopping in first gear from a stop, so I looked around a bit and noticed that there was no bolt in the rear engine mount. It was just sitting on the frame mount and there appears to never have been a bolt there (the surface was all crusty). I could lift up on the engine mount with my hand and create a gap between it and the frame mount. The strange thing was there was no hole for a bolt to thread in to the frame mount. There is a sort of aluminum spacer between the rubber and the engine mount. I wanted to test my theory last night before I came home, so I ended up drilling and tapping the aluminum "spacer" and ran a bolt through the engine mount into the spacer. While improved, wheel (or engine) hop isn't gone so I'll be looking in to an alternative.
update: thought I'd search for Corrado engine mounts and see what I came up with. This is what's installed on the crossmember, which makes sense since I believe the engine is from a Corrado. What doesn't make sense is that the engine is just resting on the rear mount. I'll end up making some mounts with urethane bushings eventually. Anyone know how the Corrado engine mount attached to the frame mount?

(what's in the car now)
vs.

Collector of Kartell relics.