Carnera has the size and power advantage, but Dave Allen is more skilled, durable, and benefits from modern boxing techniques. Allen likely survives the early rounds and wins by late TKO or decision.
Dave had the power advantage here, not Carnera, note even close. What Dave didn't have is the fixed fight advantage to pad his record. Allen would wipe the floor with Carnera, beat him pillar to post and finish him in 7 brutal rounds. Next...