Denny good to see ya bud!!!!

Tommie those 390 slugs will stick out .080 above the deck. You can mill them and run a zero deck height. BUT it would be best to check valve clearnace for any interference especially if a performance cam is used. Then you would need to machine the reliefs back into them assuring no contact valve to piston. It might be cheaper than buying new pistons if you have a good machine shop around you. Again in mind your location and shipping costs involved....G.