Can I make this work on pump gas?

Just one more vote for a thicker gasket from Cometech. It's not cheap but compared to new pistons and a rebalance it's the best option. The cost will be the gasket and maybe new pushrods. Then tune it for the lower compression ratio and have some fun! One more thing, FelPro makes a gasket that's .054 thick and inexpensive. I don't think it will be enough though.