454 - 330 HP in 18' Classic

[jyoung]

I'm looking for someone who has put a 454 in a 18' Classic as I have done. Any suggestions as to what I do now to get more speed. I've tried a 25 Mirage Plus to get 63.5 on GPS. Want more so thinking of changing 1.5 gears to 1.33 and trying a 23 Mirage PLUS. Silent Choice adds 200 RPM
1.5 gear at 4400 rpm = 63.5 with 8.6 slip

PLEASE HELP

JIM

[Len]

I would direct this to Reddog or RickR. The 72 1/2 mph 18 with a 454 and OMC KING COBRA.

[RickR]

j
You need to add 1" for a cupped prop that gives you 12.5%slip.

The 330 is not a good candidate for performance upgrades because of its cast pistons, crank and small port heads.
I am not familiar with trying to upgrade the base 454.

If your engine is rated at 3800 to 4200 rpms you may be hitting the rev limiter at 4400.
Borrow a 27 pitch prop and see what happens.

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

[falcon]

can you advise how to calculate slip, I used to use a web site but don't remember address-it would calculate slip if you plugged in #'s

[boldts]

Falcon,
Here is a site to calculate various parts of prop performance that I believe I got from right here on this site.
http://www.boatramp.com/prop_applet/PropAnalyzerAppletG.html

Scott Boldt