Decided on the final drive option and going with the billet marine swept back Bravo XR's with Billet Imcos and Hydro p5x props, Is there any added benefit from adding ext boxes ? if so where is the benefit top end mid or low ? as well as would you need to go with a shorter IMCO to compensate for the boxes or stay standard depth ? Keeping in mind I am trying to get a good all around setup and would run a poker run herring prop for full out runs.

what i found out is that the boxes will drop your x about an inch,,,you could go with -2 shorty,,and then just start spacing down ,,to get the swwet spot

what year boat is it, is it a notched transom are gimbals on the boat now? more info

2004 Hull 37 avh / ddc no step all rigging in tact.

since its all rigged, I no one gives you a pointer here go to the classifeds and see if a hull like yours is for sale. I know theres a notched trans with boxes on a older 32 AT in mass. or see if factory has a idea. other wise I would run it see how see feels or you could add imco shorties 2'' and if it cavs a lil in turns then go with standard boxes which would push you out 12'' and so you would loose a inch and stop the cavitation mostly and pick up speed. try to measure your prop shaft height from the vee angle 4'' should be perfect or 5 but 6 or 7 is deep. my boat went from 7 to 5 and picked up speed and handling. but a AT GUY SHOULD JUMP IN.

There are several 37 AVH's that have had 675-700hp. I have never seen any of them with ext boxes. I would guess that Pat does not believe they would improve performance enough to justify them. He would have the most knowledge about what boxes will do to the 37 AVH.

The 2000 37 in the classifieds is running ext boxes, I have talked to him and he indicated the boat liked the boxes, Has the factory done any testing with ext boxes ? any benefit for the money ?

Curious about this as well....bump an old thread.

The hull was specifically designed for drives bolted to the transom. That said, a few boats have had ITS in recent years. BUT, the X-dimension was changed (raised) to accomplish this. You would likely need to go to shorties or the new Mercury lower to pull it off, and the MOST you would pick up would be a couple MPH.

Since nobody is answering on the Arneson thread I'll ask here, has the boat been out and run yet? Any speed #'s???