Originally Posted by 1MOSES1 (Post 4498322)

Setup
https://i.imgur.com/eKb7CeO.jpg

Originally Posted by 1MOSES1 (Post 4498000)

So after replacing the entire valvetrain to get rid of lifter noise, upon removing engines this year for transom work; the rear exhaust valves are toasted. Heavily corroded looks like reversion. Engine has to come apart for the 3rd time. Anyone have issues with reversion on stock 500efi setup? Exhaust is cmi e top headers. They have been Pressure tested numerous times. No issues.

Before the rebuilds there was a lot of carbon build up but valves did not look like they look now. It's a stock cam, Johnson lifters, isky springs, scorpion 1.7 rockers, and trend push rods. Any help is appreciated. Thinking we may have to go dry to prevent this happening again. Going on 20k for top end rebuilds...should have left them alone.

Originally Posted by Griff (Post 4498343)

It does look like like you have the Teague style switchable mufflers????

Originally Posted by MER Performance (Post 4498349)

When you did valve springs and lifters, did you service heads with valve job ? If yes; you have a issue else where.... If you only changed springs and lifters... you have a issue due to your seats and valves that continued leaking after changing those parts. Poor valve seal or leaking exhaust will cause reversion.

Originally Posted by Panther (Post 4498360)

And make sure you don't have any exhaust leaks at the heads and also at the tailpipe connection. That will cause reversion too.

When you pressure tested the headers did you apply heat to the collector area and near the exhaust ports? I see a lot of headers that don't leak and as soon as you get heat in them, they begin to leak. People don't believe me until I show them.