There's a good chance it has allready had gas pistons installed.
Also a good chance it has broken top piston rings. Those models it is a common problem due to alum. Pistons and high hours they get.
If all of the allfuel parts are keep intact what's wrong with gas pistons and just running gas? One could likely just mill some off the top of the gas piston to lower the compression? You would have to compare to all fuel ones to check on if this is possible.