Difference between -97 50hp and -85 60 hp?

[jiipee62]

I have -97 2 cyl 50hp, and seems that I may get -85 60hp complete poverhead which is in exellent condition. Is there any difference in ignition, exhaust etc. between those two, meaning can I get 60 hp with changing only carbs and something or do I need more parts than there is in the poverhead?

Thanks,
Jyrki