Props for 13' Allison

Hi Randy, I have a 13' Allison Iím building a 82, 75 hp 3 cyl. Johnson for. So far the mods are fingerports, cleaned up existing ports, decked the block and pistons to raise the ports, milled the head to about 190-200 psi [no squish test yet] and grooved for o-rings and adapted one bank of 175 hp, 60 degree carbs and throttle bodies to fit. I have the 15" mid and the nitro gearcase from a stinger. Can you recommend some props and a starting point for engine height? 

Thanks, Allen



Try to find an old EP class OMC cleaver. 11 3/4" X 23" pitch. These were very popular in the '70's and '80's so I would think an old racer would be sitting on one. Put some feelers out on the APBA web and a few other sites. Someone will come forward and offer one up. Expect to pay $2-400 for one depending on the condition. The prop is solid hub over-hub exhaust. It is machined in the front and doesn't use a thrust washer. I wish I had the part number but it's been 20 years since I had run one.




Please submit whatever questions you have to  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Mark C.


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