Lets talk a little about extension boxes. While my 37' Active Thunder is apart and getting a new transom. What would be the plus and minus of adding extension boxes? It has a fairly high X and I have 1" spacers in currently. This AT is a 37' straight bottom boat not stepped bottom. I have heard that adding boxes to the stepped hull was not beneficial.

I really like the ext boxes on my 32, but they were on it from the factory. I can tell you my prop slip% is much lower than any other 32 that I've seen. My 32 planes out super fast and the boxes are as high as they can be mounted. I do not think they really ad any top speed. I would imagine you could easily get rid of the 1" spacers and probably still have better cruising, planing and a slightly better rough water ride. I have never seen any seen any straight bottom 37 AT's with boxes. I think there were only a couple stepped 37's with them. Outerlimits put boxes on quite a few 37 Stilettos.

Thanks Griff,
I believe the 37' is a stretched 32'? Just looking to see if a $4000 investment is cost beneficial.

Jason, I believe I have spoken about my experience quite extensively on this website years ago. Just do a search....anyway, it was with Stellings 12"extension boxes that I added----I cannot really give any back to back comparisons as I removed the Merc TRS drives when I originally bought my 32" AT, and immediately added new Bravo XR drives and added the extension boxes at that time with Standard length Merc lowers. However, a few years later I added a apir of IMCO -2" shorty lowers and the boat responded extremely well----much better ride/center of gravity/attitude/handling, and an increase of about 4+mph. I needed to go with a 5-bladed prop though, otherwise it was very difficult to get on plane.

Thanks Mark!