Jerry,
I don't have the equipment on hand to do a leakdown test, but I do have a compression tester. Here are the results (dry test, no oil added):
#1: 0 (obviously, with the exhaust valve stuck open)
#2: 70
#3: 100
#4: 100-105
#5: 100
#6: 95-100
Those readings on 3 through 6 would acceptable for an old engine, right? Perhaps the aberration in #2 is a valve issue? I greatly appreciate your input on this!