Gents- I have a Euro 380 SEL with 220K. I am getting blowby smoke typical of stem seal/ guide replacement, also some noise that sounds like the start of cam bearings (one side only).Is it possible to use US 380 swap heads? Am also debating US420 whole engine swap. Will exhaust manifolds have to be changed to fit Euro headpipes? Is this more trouble than it's worth? Anybody in the DC area that can do reasonably priced valve job??