We did an article recently about gearcase design, and how they can be modified for improved dynamics. Typically, nosecone kits are too pointy, so if you simply round the tip, you can improve the water flow. So, we tested it out on our Allison Grand Sport with a 150 Mercury four stroke. It has a customized nosecone that someone did for us, and it was too pointy. We blueprinted it by rounding out the tip, smoothing the leading edge, and redoing the edge of the skeg. We improved our top speed, and are now on the rev limiter. 77 MPH at 5940 RPM.
Here are links to the articles, one about gearcase design, and one about the Allison. The rounded tip is beneficial at faster speeds too, and can prevent blowout over 100 MPH.
https://www.wavetowave.com/home/2019...our-lower-unit
Here is the article where we did the modification to our 150
https://www.wavetowave.com/home/2019...cation-testing
.
[url=https://flic.kr/p/Rvo6rZ]Allison Merc 150