I'm going to pick Jumbo, just for the fact that he could punch really well and Wepner cut rather easily. Jumbo by stoppage on cuts in 5-7 rounds.
Wepner's peak would, i guess be 72-74, with wins over - Randy Neumann x 2 Ernie Terrell Terry Hinke Jumbo's peak 80-82 - tko over 20-2 George Mostardini dec. loss to Snipes draw with the ghost of Frazier (he deserved the nod in that one) 2 limited guys here, Jumbo could win via cuts stoppage or get stopped later on when those huge muscles drain of oxygen