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Discussion Starter #1 (Edited)
BBC 502 9.8-1 Compression, AFR 305 CNC Chambered Heads, solid roller lifters. In a heavy ass jet boat. Current cam in it, is a herbert solid roller cam part # B6H 108c 290/305 260/270 @ .050 .685/.685 lift 3200-7200, and it just doensnt feel right, had to down size my jets on the carb dramaticly....

305cc BBC CNC Chamber Aluminum Cylinder Head Flow Chart


Intake Valve, 2.250" stainless steel
Exhaust Valve, 1.880" stainless steel
1.625 O.D. Roller Dual Valve Spring with dampener 255 lbs. on seat, .750" maximum lift.
Thanks, Any Imput is appretiated....
 

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steelcomp was here
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What impeller, what intake and carb, and what exhaust? What's your goal?
Tht would be an OK cam in a lighter boat with headers, a B impeller and some compression.
 

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What impeller, what intake and carb, and what exhaust? What's your goal?
Tht would be an OK cam in a lighter boat with headers, a B impeller and some compression.
Impeller AB, Intake & Carb Victor jr 454R 850 Demon, Exhuast EMI from eddie marine.
Whats my goal; get up on plane easyier and of course top speed...Just a good chrisp running motor.....The boat fully loaded pushing at least 5000 lb..it aint ever going to see any high rpm's
 

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What is going to be your max rpm you want to turn the engine? If around 6200 rpm I can tell you that cam is way to big. I have several 502's with 305 AFR heads making 600 to 650HP and the cams are in the 230 to 240 range. Now if you are going to turn it 6800 or so that is another story.
 

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What is going to be your max rpm you want to turn the engine? If around 6200 rpm I can tell you that cam is way to big. I have several 502's with 305 AFR heads making 600 to 650HP and the cams are in the 230 to 240 range. Now if you are going to turn it 6800 or so that is another story.
6000 give or take a few hundred, the 502's you have sound like what I need. This is a heavy ass jet boat, and it will never see the high rpm's like a lighter jet would would see.
 

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Impeller AB, Intake & Carb Victor jr 454R 850 Demon, Exhuast EMI from eddie marine.
Is it run dry (no water mixing with exahaust) or is the water introduced into the tails ? If water is introduced, where ? and What fall (degrees) do the tails have ?
 

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6000 give or take a few hundred, the 502's you have sound like what I need. This is a heavy ass jet boat, and it will never see the high rpm's like a lighter jet would would see.

You are WAY over cammed for what you want.
 
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