A lot of good advice. After building and (refreshing) many engines over the years, it is always harder to do an engine in the car than on a stand. My vote would be to fix the mount and the leak and drive the car, Summer is almost here. Buy another block-engine and build your dream engine, when done put it in, You can then sell the engine you have now to recoup some costs. Unless its blowing
oil or running bad, 35,000 if built right should'nt be hurt.
Paul T