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Budget Horsepower

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Old 02-05-2008, 05:59 PM
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Default Budget Horsepower

I'm rebuilding an 1989 34' Scarab III. It's a heavy boat and with the twin stock 330HP 7.4's Top end is about 55. What would be the first thing you would do to get more power out of them or what would make the most difference without costing an arm and a leg.
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Old 02-05-2008, 06:05 PM
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How much is the budget?
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Old 02-05-2008, 06:06 PM
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How much more power and /or how fast do you want to go?
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Old 02-05-2008, 06:06 PM
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http://www.offshoreonly.com/forums/s...ight=454+roids

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Old 02-05-2008, 06:09 PM
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cams,intakes and exhaust. unfortunatly the 330's have mid level cast internals and small heads so you have to be careful how much you try and squeeze out of them.

I also have an 89ScarabIII that i am redoing the power in. Mine are 365 Mags so i have a few more options.
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Old 02-05-2008, 06:16 PM
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My opinion of my cheap boat building...

If the lower ends are in good shape reuse them, I know they are cast parts but should hole up under 5200 rpm, that is assuming they are the same as a 420 forged lower besides everythign being cast (bore size/compression)

Locate a set of rectangle port heads, too bad I just sold 2 good sets needing no work, or even go with new sets, 1800 a set or so for nice aluminums.
Maybe run the stock 400/420 cam with 1.7 Roller rockers, a good flowing dual plane intake and 750-800 Holley DP carbs.
Exhaust will need upgrading to get the most out of it.

If you shop around for the right deals these parts can be bought very affordably, I found a deal where I got two complete engines with merlin heads, and single plane intakes, kept all that made my money back on the remainder of parts and I have cool stuff for free, I am serious budget guy, helps that I do all my own work though.
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Old 02-05-2008, 06:22 PM
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The 330's are no good for bumping up horsepower, they do not have the good internal parts and If I remember the heads are smaller than the 365's also. If your going to keep them rebuild and run them, they are reliable as is.
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Old 02-05-2008, 06:24 PM
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I have seen alot of guys make decent power with them, they are still a 4 bolt block, well... most are. the parts inside should be fine till around 425 ish HP and 5200 rpm from what i have read and heard.
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Old 02-05-2008, 06:28 PM
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The blocks should be four bolt mains. The cranks are cast, the rods are the small bolts, the pistons are cast. The heads, cams, intakes, carbs, and exhaust can all be upgraded. You should be able to get 400 to 450 HP with reliabilty. If you don't do your own work pick a reputable engine builder. There are several on here.
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Old 02-05-2008, 06:41 PM
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Quote:
Originally Posted by 245 limited View Post
My opinion of my cheap boat building...

If the lower ends are in good shape reuse them, I know they are cast parts but should hole up under 5200 rpm, that is assuming they are the same as a 420 forged lower besides everythign being cast (bore size/compression)

Locate a set of rectangle port heads, too bad I just sold 2 good sets needing no work, or even go with new sets, 1800 a set or so for nice aluminums.
Maybe run the stock 400/420 cam with 1.7 Roller rockers, a good flowing dual plane intake and 750-800 Holley DP carbs.
Exhaust will need upgrading to get the most out of it.

If you shop around for the right deals these parts can be bought very affordably, I found a deal where I got two complete engines with merlin heads, and single plane intakes, kept all that made my money back on the remainder of parts and I have cool stuff for free, I am serious budget guy, helps that I do all my own work though.
Can you recommend a cam (specs) and intake?
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