340valve train noise with new head gaskets

i talked to a guy at the mopar tech line and he told me to just check and see what length i need.same thing at smith brothers pushrods.the peole at felpro and summitt just couldnt find any answers ,at least summit referred me to mopar all felpro did was make excuses he didnt even have an idea to try changing to thinner gaskets .i have a push rod length checker coming .thanks for everyones ideas. it just sucks that when you try to do something right and make it better all these problems come up.