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[BrendellaJet]

Let me ask this, what is 10.5:1 going to give me that 10:1 wont? Im just looking for horsepower. The boat will be used for my personal pleasure. I would like it to rev to 6K rpm or close to that figure. I want it to be reliable, but fast, or atleast as fast as reliable will allow. Im entertaining some other options for making power, but I want to make sure I can optimize my current set up. If you think that 10:1 is the limit for iron heads, then I am going to take your word on that. But if 10:1 cant get me to 6K RPM, then I need to raise compression right? I will upgrade to aluminum if you think that would be more wise.

[Hotcrusader76]

BrendellaJet:
Let me ask this, what is 10.5:1 going to give me that 10:1 wont? Im just looking for horsepower. The boat will be used for my personal pleasure. I would like it to rev to 6K rpm or close to that figure. I want it to be reliable, but fast, or atleast as fast as reliable will allow. Im entertaining some other options for making power, but I want to make sure I can optimize my current set up. If you think that 10:1 is the limit for iron heads, then I am going to take your word on that. But if 10:1 cant get me to 6K RPM, then I need to raise compression right? I will upgrade to aluminum if you think
that would be more wise.What I said is to run aluminum would mean being able to run pump gas. You can run iron at higher compression ratios, no problem. But plan to run nice high octane fuel to keep from detonating.
Also consider a new Blow-through carb set-up from paxton. Its sort of exotic, but it seems to be the new wave of reliable HP. Plus you only have to run 8.5:1 or so.
I honetly think you can squeeze some good numbers with 10.5:1 on pump gas, good idle, and great RPM's.
Sacrifice....gas mileage, but you can still get it at the pump! Or consider coating your piston tops with a professional coating, and getting aluminum heads, then you can run 11:1

[FLYTE RISK]

If you can afford aluminum go with it.. I have dart pro1s.. Lots of port work on mine butt right out of the box325s will get plenty of H.P For your combo.. Just remember intake mani oval or square more $$$$$$$$

[Dave F]

Ok. What you have to decide for yourself is, how much money do I want to spend?
Where can I get the most bang for my buck?
In my opinion, for your app, I would use iron heads not aluminum.
Iron will make more horsepower (generally) than aluminum using equal compression ratio.
You said you want reliability. 6000 r's are less reliable than 5-5500 r's.
10:1 is more reliable than 11:1.
For your criteria (reliable)I suggest the following:
10:1 max with iron heads. You can run on pump gas that will cost around $1.90 rather than $4.50.
Aluminum are subject to salt corrosion are suseptable to blowing head gaskets especially if you get some sand sucked up and over heat. They blow the gasket when they overheat because they warp. That means more machine work to fix.
At 11:1 it's much easier to detinate. Cylinder temps will be much higher and it only takes a bad batch of gas or some water in the fuel and the motor's gone.
Spin the motor no more than 5500. In that range with 10:1 you can use a cam in the low to mid 230's intake and high 230's/low 240's in the exhaust. 112 lsa and a 107 icl and around .
600 lift.
With proper work done to the heads, good exhaust and good intake that combo is in the 500+ hp range.
The relationship of $ and reliability go hand in hand.
Like I ask anyone who want's me to build them motors, "how much do you want to spend?"
DAVE

[BrendellaJet]

Okay, I think I'll do that. Those #s sound good. Thanks Dave! By the way, what is that cam going to sound like at idle? And about how many RPM will it idle at?

[v-drive]

BJ, how is your yard coming............pop

[Dave F]

With the right exhaust it will have a great "lopey" sound. You will definatly "rock the dock" as they say.
You'll be able to idle at 800 and in gear between 6 and 700.
Getting back to the exhaust. You will need, if you don't already have, after market exhaust.
This size cam will cause reversion on stock Merc exhaust.
DAVE

[BrendellaJet]

I think ive got the exhaust covered with my Bassett twisties!!!!!

[Dave F]

Excellant. Good luck!
Hope the combo works out for you. Keep us posted.
DAVE