Call Dean at the B-Max and he will tell you what to do. If the B-Max can not handle your engine then the #6 is the next step. I personaly think B-Max is the answer.

Clueless
I have a friend who has a full season on a B-Max with 1300
plus hp ,this year he is trying for 1600. Sat. is dyno day for the
monster:cool:

When you bought the drive from Imco did you tell them the HP you would be pushing through it? 900hp/tq is huge and would think Imco might steer you away. I know they do not offer warranty. It seems awfully expensive to "try" the same thing 3 times.

I know of a Carrera 257 on Lake Norman, NC with 1300 HP and 1200 ft/# that torched 9 bravo's in 2000. Went with the B-Max last season..no problems.

Don't forget about the size/weight
 

A big factor often left unsaid is boat size and weight relative to drive life. I know it's an exaggerated length Fountain but it still has considerable wt and wetted surface area, especially for that power.

I suspect the first two imcos were not the "SC Advantage" that you have now with the new beefier upper housing, pinion support and the XR gears. That drive should be a significant improvement over what you had but may not be enough.

If it's only got 5 hrs I would sell the upper and run the Bmax upper- huge difference in torque capacity, size of gears etc. Talk to Dean maybe you can swap uppers, keep your lower etc. Good luck!:D