In my opinion, with that wild cam, the riser would need to be 3 or 4 feet long NOT to revert at idle. From all the descriptions, I'm sure that it is reversion.

would a warmer thermostat help the mechanic working on it wants to try that. It has a 160 now Is this really a good idea with it being an efi ?

I wouldn't really call that cam 'wild' by any means. Could an exhaust revert with it ? maybe - but it wouldn't be a good performance system if it did. Remember, it has 224° 230° at .050" ground on a 114° LSA. Unless actual overlap is huge, but it appears not with only 5° overlap at .050: and the rel short deat duration. I know - .006".

The 500EFI cam is 'bigger' than his.

Is this exhaust set up for silent choice ? Meaning: super short risers ?

Or 'copied ' cam specs incorrectly ? Comp likes 110° and 112° LSA cams, but your part# doesn't come up with a card online. Maybe custom ground cam ....

I really want to thank everbody for all the imput I'm not mechanical and really about to pull my hair out. I rechecked specs copy I was supplied with. I can't see where i missed anything I don't even understand them anyway .couldn't get part # to pull up ether 11-000-8 serial# c4116. anyway I have the dana marine long aluminum risers not the short ones for silent choice. maybe I should try the stainless vortec ones I know it would be cheaper and easier than new motors THANKS AGAIN for all the help