Karl, there's nothin' not good about that big Delta TS. If you can swing the size, all is well. Probably the worst would be if new arbor bearings are needed, but that is to be expected over years. Check pulleys for loose set screws. (some may have two piggybacked set screws) Check the quad belts for wear.
Here's a parts diagram to download if you do not already have it:
http://vintagemachinery.org/pubs/detail.aspx?id=531
Tune the big saw up as you would any smaller cabinet saw. An internal cleaning with compressed air and dry Teflon lube of moving parts should get it adjusting smoothly. With your paltry (You Suck!) investment, you can certainly afford to find the right single-phase 5hp motor.
The existing Size 1 (rated 30A) magnetic starter contacts should be heavy enough to handle the 1ph amperage. But, remember that overload heaters will have to be changed out to reflect the higher amperage of the new motor. The old 3ph motor was around 13A on three legs. Your 1ph motor will be around 21A on two legs.
Good Luck, Enjoy!
~~Chip~~