Thanks for the response. I considered wacking, dimpling the valve covers but decided against it. I found the valve cover spacer on Mancini's web site and decided to go that route. I would like to use the thinnest but best gasket possible. I called Mancini and the spacer cannot be used as a gasket, so it needs to be sandwiched between two gaskets. The spacer is .188 thick. Mancini sell spark plug tubes, and o rings, that are 1/2 taller than stock.
I guess the big question now is what gaskets to use????????

Thanks again Bob,