Allison Grand Sport Mercury 150 update

[Wave to Wave]

Here's the latest on our project 150. We had the lower unit done, and did some preliminary testing. Got some mileage numbers at higher speeds, really impressed so far. With a little more setup, should get to 78 MPH. Hit 76 so far, with a few tweaks yet.

Article
https://www.wavetowave.com/home/2019...on-grand-sport
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[Apple Allison]

Thanks for the great information! This must be a very smooth running rig. What would you think of using a new four stroke Merc 225 or 175 Pro XS V6? Both would add about 20 pounds to the package over the 150. Also do you know how big of a hassle to convert to solid mounts? I currently run a 200XS on an XB 2003 and am looking at repower options.

[Wave to Wave]

Thanks for the great information! This must be a very smooth running rig. What would you think of using a new four stroke Merc 225 or 175 Pro XS V6? Both would add about 20 pounds to the package over the 150. Also do you know how big of a hassle to convert to solid mounts? I currently run a 200XS on an XB 2003 and am looking at repower options.

Hey, sorry for the late reply. I personally think the V6 would be a bit too heavy for the Grand Sport. We converted to ProXS upper mounts, and on the 150, it is relatively easy. The uppers are way easier than the old engines, you can access them by removing the top and side cowls. The hard part would be getting them made. The ProXS uppers are stiffer, the lowers are the same as the stock 150. We may look at making the lowers solid. Could maybe get someone to fab them out of Delrin, that's what I plan to do. A ProXS 150, would be a great on this. If you could adapt a 3.0 1.75 sport master, it would be amazing.

One advantage the V6 might have, is the mounts might be compatible with the Racing lower mounts from the 250R and 300R. That I can't confirm though.