I would try upping the compression ratio. Maybe use the 0.020" thick steel shim gasket? I see Summit lists Mopar #P4286754 for $21.95/pair, but out of stock, and says to use Mopar DCC-5155237 which are $159.95 Mr Gasket has the #1135G (0.020" thick) one for $21.95 /each. What other cams do you have to choose from?