stylewise this would be very hard for Frazier. But in this case Frazier would have a chance to maybe hurt and stop Foreman. People forget that Frazier weighed near 205 when he fought Ali. not a very big heavyweight.
There would need to be a drastic loss of power from Foreman for Frazier to ever be capable of beating either the 70's or late 80's/early 90's incarnation.I'd genuinely love to be able to put together a convincing argument together for Frazier,but he get's killed to death every single time.
The old version of George would be strong enough to hang in there till the end,but would lose a lopsided decision to Joe.
The 1971 Frazier was relentless, fast punching, could quickly bob and weave and roll with punches. I believe the Old George would not be fast enough to consistently land on '71 Joe to do the damage he did in '73 and '76. I believe this fight would go the limit, with no knockdowns, and Joe outworking George to win a comfortable decision.
Frazier gets owned again. He still eats powerful uppercuts. Foreman may have been slower but he got wiser and craftier and still has a mean uppercut. Bad match up for Frazier
Foreman by knockout. As fast and formidable as Frazier would be, old foreman still cuts the ring off and lands big. Frazier may wobble and stun foreman with The left hook, but old foreman's jab and uppercuts would be joes downfall.