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cam selection help

Old 05-21-2012, 08:47 PM
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Join Date: Jun 2011
Location: Baton Rouge, La
My Boats: 1998 velocity 280
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Default cam selection help

I finally got my cam specs for the cam that came out of my motor. It turns out to be a 500 mpi oem style replacement cam (thanks Bob Marine Kinetics).

If Bob reads this I hope he comments. I have called him many times over the last few weeks with questions and he has been a great resource, I hate taking up is time at his shop.

Here are the cams as follows:

cam that I used last season
In .506 lift
Ex .509 lift
In dur 223
ex dur 223
115.7 lobe seperation

option 1
in 544 lift
ex 537 lift
in dur 231
ex dur 236
114 lobe seperation

option 2 (comp cam)
in 544 lift
ex 547 lift
in dur 226
ex dur 236
112 lobe seperation

-motor is 468 with flat top pistons
-new heads are 781's with 2.19 1.88 valves, gasket matched, bowl blending etc.
-dual plane pro comp (edolbrock knockoff) intake gasket matched to new heads
-going with a 850 holley carb from a q-jet
-looking for a set of gil manifolds or something similar to get rid of the stock mercruiser manifolds
-crane gold roller rockers

I don't plan on going over 5000 rpms as I have cast crank and 3/8 rods.

I'm leaning towards option 1 due to Bob and cam motion suggestion. My main question is roughly how much hp am I looking at compared to the cam I just took out? Some friends are telling me not to bother because it won't be worth it, but its hard for me not to upgrade it there is power to be had (bad habit I guess)

Boat is a 235 force that I was getting 63 mph (hand held gps). Motor was basiclly a 330hp 454 except it had the cam in it (which likely wasn't helping with the peanut port heads and stock manifolds...I don't know)

Thanks for any opinions or suggestions!

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Old 05-22-2012, 01:50 AM
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