I think it'd look something like Taylor-Chavez to be honest except Chavez stops him a round sooner. That's at LW though.
I bet it would be a hell of a lot more on target than "Pac on steroids, JCC KTFO Pac" and "Pac by TKO" without any sort of substantial explanation. I know that much.
I don't think there would be any stoppage in the fight. It's a tough one to call but I think JCC being rated the best Mexican fighter ever and seeing how many great Mexican fighters there have been, I can't see Manny topping him in the p4p all time list. Manny is special though, beating Barrera, Morales & Marquez.. also De La Hoya & Cotto... the chico killer