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View Full Version : Thank you all and a prop question



8318
07-08-2009, 07:22 AM
I wanted to thank all of the users of this board for your help in my repower of my 83 18.
I did not post many questions as the search button provided me with hours of information.
The new motor is in and the early numbers look great.
old was a 383 with a mild cam.
Boat ran 70 off the speedo ( no gps) and turned a Laser 2 -26 inch pitch prop to close to 5 grand Alaph one SS 5.1 ratio.

New engine dart 400 11.1 comp roller can solid lifters Jessell shaft rockers
Blake carb lighting headers, all put together by a well know engine builder.
Last night I got to run the boat for the first time and it was inpressive.
I know these numbers are inaccurate as they are not from a GPS however they are great to use as a comparison, given that the only differance is the engine.
The boat ran just shy of 80 at 6 grand and was still pulling. Same prop and outdrive.
In the past I would need to trim the boat out to reach 70 now I can hit it with no trim and more throttle to go.
I am lucky with this boat as it is rock solid in the water no chime walk or prop blow out. The boat feels as solid as it did before just faster way faster.
This leeds me to my question,,,what prop to try?
I know that props can change so much of a boats handling qualities.
I know I need to try a bigger prop but I do not want to loose any of the stability that the Laser is providing.
Thank you again for all the help.
Dave

BlownCrewCab
07-08-2009, 07:48 AM
If you can run 80 and have no chine walk and the boat feels solid, then the prop you have is Very close to perfect. It may need a tweak or two to get Max speed Preferred rpm but I wouldn't stray too far from what you have.

Just Say N20
07-08-2009, 09:44 AM
Congratulations!

While the handling is great, as is the performance, you will need something with at least 6" more pitch. If you are turning 6,000 rpms with more throttle left, you are running well into the danger zone with the SS outdrive (just my opinion).

Hopefully the engine builder designed the engine with peak hp @ no higher than around 5,500 rpms, because most outdrives don't like running above that. If it is still pulling, it sounds like peak hp is way up there in the rpm range. Time for an Arneson. :yes: