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  #46 (permalink)  
Old 11-03-2008, 10:37 AM
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Hey,
Thats a first, I taught someone on here something lol. Glad to let ya know this, but yes, thank you for pointing out blowing myself up, as If i had not reasearched boats and been boating for 12 years now, so I know some stuff, but there is always room to learn. I just know you surely do not want any gas fumes any where in the Engine compartment.

When I first purchased the boat, the blower hose had fallen off, I found this before I even started it, but the Previous Owner had been using it that way, so I was like man, thats crazy! Could have been a big boom for sure, but I run my blower all the time while running low speeds and even high, I dont care, would rather burn that out then blow up!

Bryan

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  #47 (permalink)  
Old 11-03-2008, 12:31 PM
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bryan,
I couldn't open you cam spec's link....

so just food for thought and research:

most marine cams do have a hell of alot of "advance degrees" ground into them when installed "straight up" which shifts the TQ curve lower and helps out of the hole TQ...

"but"
the same cam advanced position motor is used in many different hull designs and boat weights and props....
so it is a compromise setting for launch TQ versus speed HP.....

shift a stock motor cam just 2* more advanced can make a 30ft/lbs+ difference at 2k with a stock intake ,,,,from 255 typical stock to about 300 at 2k with the dist re-curved and carb tweeked is typical/reasonable.....

you changed the "inhale" characteristics but the cylinder head "exhale" characteristics are still stock....
depending on the cylinder head intake to exhaust cfm ratio and exhaust port design efficiency it can help to change to a 1.6 rocker ratio...
that dramatically increases the actual valve lift for more exhaust cfm flow....
which can help pull more charge into the cylinder to make more power.....

it may well happen that 1.6 rockers on the intakes and exhaust rockers works out best because of the crosswinds intake does want more cam.....

apply all of the info we have posted to a 350 long block and the 2900lbs will jump up on plane.....

there's only so much you can do with 300 cubes versus a 2900lb gorilla
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Old 11-03-2008, 01:27 PM
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I agree RedMustang.

I think I read in one of the manuals, that the Rockers were 1.5's, and this is all new to me. So I am not sure what it is actually. The exhaust is 4 inche pipes that come straight out the back, with the Stock headers. They breathe pretty good though.

Heres what the Cam shows, I think.

Flat Hydraulic
Roller Arm Rocker Ratio 1.5 to 1
Valve Lift Intake .394 (10.00)
Valve Lift Exhaust .404 (10.26
Valve Lash (intake and Exhaust) 1 turn down from Zero
Face Angle Intake and Exhaust 45 Degrees
Seat Angle Intake and Exhaust 46 degrees
Seat Runout Intake and Exhaust .02(max .05)
Seat Width Intake .03215-.0625 (.79-1.58)
Seat Width Exhaust .0625- .09375 (1.58- 2.38)
Valve Diam Intake 1.84
Valve Diam Exhaust 1.5


Bryan
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  #49 (permalink)  
Old 11-03-2008, 03:08 PM
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bryan,
that's not enough cam info....

because you didn't say what the motor "vintage" is I picked this cam card just as a example only as to what all the details look like:

http://www.cranecams.com/?show=brows...tType=camshaft

click on the "Knowledge Base" link at the top of the page, then engine section, then valve train section (articles) for a more clear understanding on valve trains....

all the cam grinders sites (comp/lunati/isky/etc/etc) do have excellent "tutorial" articles as well on tuning a motor with the cam advance....
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Old 11-09-2008, 07:55 PM
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keep it simple

To keep it cut and dry use a bow tie marine manifold GM# 14096011. Itis @ $200 available at any gm dealer. Its casting number is #14096242. The manifold can use square bore or spread bore carbs and will bolt right on your heads. Almost all merc cruisers use rochester Q jet or 2bbl. Your stock camshaft will make the most torque for your application. If you decide on a bigger cam you need to match it with some heads. I recommend patriot-performance 185cc iron vortec heads. Use lunati voodoo series cams like the #1000lk for a 305. Voodo cams are ground on a 112 for marine applications.
I recently built a 406 chevy for my 24' cruiser and did the homework. Boaters dont need to shave tenths and do 11's in the quarter. Its hammer down to plane and do 50 mph!
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