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Greg Guimond
02-29-2016, 04:32 PM
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Very roughly what would a mild 454 Twin Turbo motor make for ponies? I believe that the 80's vintage 454 Magnum's made 365hp but I'm curious what the set up below might make to push the boat to 80mph?


1988 23' Crusader Boat and Competitive Trailer. Not many of these were made and its a classic. 454 Twin Turbo with Mercruiser Bravo One outdrive. Motor and turbos were rebuilt a few years ago but there are very few hours on it since we have rarely gone to the lake for several years. Has awesome sound system in it. Comes with two SS props, 19" and 20". Trim tabs, thru transom exhaust. Boat runs amazing. Will do 80 MPH in right water conditions. New windshield. New trailer tires. Boat upholstery is original, still useable but might need to be replaced. Could use a little wet sanding but still in great shape. A couple little rock dings but very clean.

Ed Donnelly
02-29-2016, 06:32 PM
How many lbs boost, waste gates?...Ed

BUIZILLA
02-29-2016, 06:33 PM
80 with a 20" prop? :rolleyes:

Lenny
03-01-2016, 11:28 PM
I want someone to put an NRE in their boat normally aspirated

https://www.youtube.com/watch?v=9K4g0bKEtBU

duckhunter
03-02-2016, 11:23 PM
80 with a 20" prop? :rolleyes:

Yup, that was my first thought as well. That's a ton of RPM for a marine BBC. Curious to see the plumbing as well.


I want someone to put an NRE in their boat normally aspirated

https://www.youtube.com/watch?v=9K4g0bKEtBU

If I ever hit the lotto Tom Nelson is getting a bunch of money!

Ghost
03-03-2016, 12:13 AM
Had the same thought. Ran it through the prop calculator the other day. Seemed like with about 5900RPM and 1.36 gears you could do it with about 3 or 4 % slip. Lotta planets need to align.

Just Say N20
03-03-2016, 06:57 AM
Had the same thought. Ran it through the prop calculator the other day. Seemed like with about 5900RPM and 1.36 gears you could do it with about 3 or 4 % slip. Lotta planets need to align.

Exactly.

Greg Guimond
03-03-2016, 08:00 AM
Thanks guys. Sounds like the boat is probably an honest 70mph any day of the week with that set up and not 80.

turbo2256
03-03-2016, 08:19 AM
In general every 10# of boost = doubling the the size of the engine NA .... A 350 with 10 lbs of boost would put out the same as a 700 cu in engine NA

Greg Guimond
03-05-2016, 11:42 AM
.............