99 Donzi Z22BR 383
09-04-2017 | 08:29 PM
#11
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From: Woodstock, Georgia
Rule of thumb is over 1.0 hp per cubic inch is expensive and unreliable. Put a 454 in it. Aluminum heads and it is essentially the same weight as the small block you took out. But you spend 3 to 5k and speedo will say 62 instead of 54. It is a paid for reliable nice setup.
09-04-2017 | 08:36 PM
#13
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From: Toledo Oh
s will work, the holes for the thru hull exhaust will be different, But then again if you start building on the small block you will eventually need better exhaust with could possibly throw the current holes out the window too
09-04-2017 | 08:41 PM
#14
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From: Woodstock, Georgia
I just googled the boat..it looks to be less than a 24 degree bottom? and it has a pad? and your seeing 48 mph gps with 300hp thru an alpha?
Before you start building anything, figure out whats wrong first. If its the bottom I saw in the google pik, with 300 hp you should be 10 mph faster.
Before you start building anything, figure out whats wrong first. If its the bottom I saw in the google pik, with 300 hp you should be 10 mph faster.
Last edited by Donzi Z22; 09-04-2017 at 08:52 PM.
09-07-2017 | 04:50 AM
#16
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From: Cedar Creek, TX
475 hp with a 383 should be fairly easy with the right parts. I have a 355 built 20+ years ago that made 424 hp on the dyno with dyno headers (and it is EFI with all of the stock 1987 model 320 EFI hardware). With stock Mercruiser style manifolds and risers, my boat has run a best of 72 GPS with 2 people and light fuel. Mine is a 20 ft Checkmate with a very similar bottom to yours (V with a pad about the last 6 ft).
