Building Merc 454, need advice...
#11
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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 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???
Last edited by randymbtech; 03-02-2011 at 05:18 PM.
#12
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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
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I was told the same exact thing.
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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 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???
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#16
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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.
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sent you a pm
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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.