If he has the title, but it's signed, then you simply look at who it was last titled to, find that person, give them a hand full of dollar bills, and ask them to make a trip the DMV to get a duplicate title printed in their name so that they can sign it over to you, it's that simple, the hard part with missing titles is finding out who it was last titled to, unless there is paper work to give you a clue it can be nearly impossible, this seems simple.
That's a wild potbox! I'd guess it's actually a big rheostat, or an array of discrete resistors, rather than a carbon-type infinitely variable sliding resistor.
Another thing I noticed is the motor itself looks fairly small. Diameter is similar to ours, but length is much less. Keep in mind with our motor mounted with the tranny on the 3-cyl mounts (as this one is), our motor almost touched the right side frame.
For comparison - this is our motor in the 4-cyl offset position (offset to the L is about 4 inches). Motor is 15 in. long: