Fox Old Engine, Blown Head Gasket, New Heads?

With 220K and ripped down to the heads, I'd be rebuilding or replacing the bottom end.

With that many miles on the motor, I suspect when you throw new heads, gaskets on it that the motor will reveal it's other weaknesses- rear main seal, bearings, etc.

Sounds like you have two options
1. clean up the stock top end and reinstall with new gaskets while you build another motor
2. put a new top end on while you build another motor, knowing you will transfer over the existing top end

With #2 you are limiting your choices as you may end up going a different route than a stock 302 bottom end. If it were me and a 200k+ bottom end, I'd do #1. You don't just install heads- there is all the supporting parts like intake, cam, injectors, MAF, headers, rockers, pushrods, etc. The least expensive way to do it would be some explorer heads and intake. You would only have to change the springs on the heads and could keep everything else from the stock motor. Probably 6-700 when all is said and done.