Yah, the mufflers are long gone, the previous owner had a bunch of hose and elbows rigged-up, it was terrible. I am going to try and make it nicer with some stainless 90's and 4" hose.

I am staying with the flat tappet, hopefully this cam will not create a reversion problem. I am going to call Comp Cams again tomorrow and make sure.

I have the 049 casting heads, which I was told are oval ports, not peanut ports???

I didnt think any Mercruiser engine came with peanut ports. Those oval ports should be good to 400+ hp before they become a serious restriction. 454 Magnum heads have ports that are so big the motor could never hope to use all that available airflow

I was told the same exact thing.

049 are a good large oval port head and would respond well to more cam. You said 904 head earlier and yes, 330 mercs came with the small oval port heads. That is how they make so much down low torque.

Sorry about that, they are 049's....typo!

Last flat tappet cams I ran with my 454s (rect port heads) was the xm278h-12. 564/567 lift 234/44 dur. 112lsa. It reverted some even with the imco SS risers on the merc manifolds. I eventually switch to diff exhaust. The xm262 would work well for you and is comparable to the 365hp cam.

That's good news, I appreciate it. What type of exhaust did you switch to that stopped the reversion?

sent you a pm

Have rmbuilder grind you a custom cam to match your head flow numbers. It will be worth it. I'm guessing something with about 226/228, .530/.540 on 115 lob sep.

Keith Eickerts. That even didn't stop it totally. I eventually added inserts into the tailpipes that keeps the water seperate from exhuast gas until it exits the tips.