Rusty O\'Toole wrote:
I have a feeling that a year or 2 from now someone will be trying to sell a 37 Packard with a chev engine, and be ticked off that not only can he not recoup the cost of conversion, but the car is worth less than when he started.

Of course by that time the original engine, transmission, rear axle, radiator etc will be long gone to the junk yard (who wants that old junk?) so it will be practically impossible to restore the car, or get its value back.