Has anyone tried ITS Boxes on an 05 38 Lightning or same model boat? If so how much did you gain from it? Did the Sportmaster 2" Shorties & Hering 32p 6 Blade props. Mid range and top speed were much better hits 90 but coming up on plane sucks. Just slips like crazy till it catches. Might try a 1" spacer and see if that helps.

Mine did the same thing w 6 bl. I am going to try 5 bl next. My boat works well w 5 blade maximus props . But I will try the 5 bl Hering to see If I can raise the top end. Too hot here to run WOT right now. There was a 04 w extention boxes that a guy named Al on here had .

I had a 03 38 Lightning with 525's and a semi-stagger set up. We installed Stellings extension boxes and 2 inch shorties on this boat. The final best set up was the prop shaft 1/4 inch above the bottom of the boat and 31 pitch Herring 6 blade props. The boat ran 96 to 98 mph with this set up. It also ran well with 32 pich Bravo 1 props and would run 94-95 and the engines were very happy. This is also much easier on the drives. Also tried P5X Hydromotive props and they worked well but not as good as the others in my opinion.

Those are some really impressive gains. With the shorties and my 31 Herrings it hits 90mph at 5200 rpm. With labbed 32 Bravo 1's hits 89 at 5400 rpm bouncing off the limiter. Did you have a different gear ratio? Mine are 1:50.

It is also a 1.50. The results are from a lot of testing Nd modifying props and drive heights.