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Cole SS
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Discussion Starter #1
I have a standard 454 marine 330 hp 1990. I am trying to figure out which cam to use. I figure someone on this site has used either one of these. I am looking at a comp cams xm270h vs xm278h. Boat is 20' openbow cruiser. Used mainly for fun family boating. I would like to use the stock short block. Will have 049 mild ported heads with larger valves, performer rpm intake. I would like to use the stock 715 carb. I can't afford headers so my stock / snail riser exhaust will have to do. I am looking for a reliable more than stock motor that will not break the bank. Any of your thoughts would be appreciated.
 

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E-7 Sheepdog (ret)
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6,834 Posts
I have a standard 454 marine 330 hp 1990. I am trying to figure out which cam to use. I figure someone on this site has used either one of these. I am looking at a comp cams xm270h vs xm278h. Boat is 20' openbow cruiser. Used mainly for fun family boating. I would like to use the stock short block. Will have 049 mild ported heads with larger valves, performer rpm intake. I would like to use the stock 715 carb. I can't afford headers so my stock / snail riser exhaust will have to do. I am looking for a reliable more than stock motor that will not break the bank. Any of your thoughts would be appreciated.
I have a solidly reliable 454, that was dead stock Indmar 330HP 454 5 years ago, and you already have almost all the work I eventually managed to do (same intake, ported '049 heads). Ran my stock 700CFM 4150 untill just this past summer.
I overhauled the engine in 2004/5, put on the manifold, and was advised by a friend of mine who works performance jets for a living, due to my uses and intentions, I should go with the Isky 280H, bought the full kit, and love it.
It was perhaps a bit big at the time with stock heads, logs, and 700 Carb. It is still a great cam, keeping up just fine as I have managed the rest of the mods (including Lightning jacketed headers).

The springs are pretty mean for a Hyd. Flat cam, put roller rockers on it. My stockers were OK untill I pushed the engine to 5400 RPM, then they started cooking. Friend set me up with a set of Comp Hy-Tech Stainless Steel rollers, used, got them rebuilt by Comp, and still spent less than new Pro Magnums

You'll likely need longer than stock studs for roller rockers too, if you haven't already.

It's a great cam, but your log exhaust will be holding you back pretty heavilly. As soon as you can find $2,000 for Lightnings, I'd put a set on. You'll like the results.
 

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I have a standard 454 marine 330 hp 1990. I am trying to figure out which cam to use. I figure someone on this site has used either one of these. I am looking at a comp cams xm270h vs xm278h. Boat is 20' openbow cruiser. Used mainly for fun family boating. I would like to use the stock short block. Will have 049 mild ported heads with larger valves, performer rpm intake. I would like to use the stock 715 carb. I can't afford headers so my stock / snail riser exhaust will have to do. I am looking for a reliable more than stock motor that will not break the bank. Any of your thoughts would be appreciated.
And the addiction begins:D
 

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Cole SS
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139 Posts
Discussion Starter #6 (Edited)
Laugh it up, the question still stands. I am not looking for race boat. Just want a nice strong family boat. I already have a little hot rod boat. To rough on big lakes. Want to keep wife boating and safe for kids. Yes a pleasure boat if you will. Does not mean I can't have strong cruiser. Just looking for some honest imput before I make a choice. I don't have a lot to spend on this boat. All you racers can ignore my question.
 

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Xm270h

Laugh it up, the question still stands. I am not looking for race boat. Just want a nice strong family boat. I already have a little hot rod boat. To rough on big lakes. Want to keep wife boating and safe for kids. Yes a pleasure boat if you will. Does not mean I can't have strong cruiser. Just looking for some honest imput before I make a choice. I don't have a lot to spend on this boat. All you racers can ignore my question.
the 270 is my choice based on what you are wanting,should be a real nice cam.
best of luck
:)hand Travis
 

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E-7 Sheepdog (ret)
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6,834 Posts
Any of the 3 would work almost equally well (your 2 choices, or mine).

Get rid of the logs eventually and I'd want bigger than the 270, just M.O.

I have the strong-running relaible family lake cruiser, a "race boat" is something a Taylor SS will never be. LOL She's way too heavy.
 

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Laugh it up, the question still stands. I am not looking for race boat. Just want a nice strong family boat. I already have a little hot rod boat. To rough on big lakes. Want to keep wife boating and safe for kids. Yes a pleasure boat if you will. Does not mean I can't have strong cruiser. Just looking for some honest imput before I make a choice. I don't have a lot to spend on this boat. All you racers can ignore my question.
I meant you no disrespect, I was just jumping on the bandwagon and having some fun. Wives and children can be pretty intolerant of any boat that sounds more aggressive than the truck used to pull it. Coupled with the mild motor, logs with snails, and smaller carb, I would choose the 270. There, hope I made up for any misgivings, F1~
 
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