Have dry exhaust till the last inch of the tail pipes , still have reversion . Did someone solve this issue ?

Cut last inch off. What cam you have? Also when you mention reversion what do you have milky oil or did you physically inspect your exhaust and ports and see moisture... long idle time?

Yes have a bit of milky oil cam is 244/236.

The good news is reversion doesn’t cause milky oil, but the bad news is many other things do. Cold water, cold oil, bad intake gaskets, blown head gaskets, failing oil cooler, and the list goes on. A lot more info is needed to even guess.

The problem is that this is a fresh build everything new gasket, ssm exhaust . Can I do internal flappers on a dry exhaust?

No had as well but much wrest because of Exhasut failure