Eric,
Are you aware of any information on the engine when it was last running? Miles on engine, compression, etc? I've been in correspondence with two other sellers with the same engine, one complete with transmission like yours and both listed at $300 - similar situation where cars have been rodded so running gear became surplus. What held me back was that neither had any idea what condition their engines were in and thus complete unknown on how they would fare as rebuilds - versus rebuilding the engine that I have.
If you have any further info on the engine I would be interested. Is the engine still free to rotate? With low compression it should be relatively easy to rotate from transmission in 3rd gear (down to right). With freight the $600 is too steep for my budget but if it doesn't sell for your asking and you can confirm the engine isn't seized after sitting for 30 years I could still be interested.
Best,
Jack