Help on 408 build
In my opinion anything other than changing pistons is half ***, and likely they cheapest solution in the long run if the engine has that much squeeze. Some of the replies are telling him to change the heads to aluminum and the cam... now that is spending money.
Your head gasket idea is fine but if you have to cut the intake or buy push rods to make them work you might as well put the money into pistons...you will likely be ahead in the end. You will also have a set of pistons you can sell and likely get half about half the price of the new set.
As far as closing your shop because I gave someone a bit of different advice on the internet on how I would tackle the problem that’s up to you...