I have a 2007 Formula 370 SS. I recently upgraded the engines to 700 HPs. Has anyone modified a 370 or 400 ss like this? I am still running on the original Bravo III drives and need some advice on different props to get more speed out of it. Currently running into redline on original 26P props.

Bravo threes are not intended to be high speed drives. Once over 60-65 mph they have way too much drag and start causing problems.

With a heavy boat and big power you should be considering a heavy duty drive like an IMCO. I wouldnt even bother putting a Bravo 1 on.

You can try going to a propset having 30 inches of pitch but you will never reach the full potential with those drives

in that boat you should change the drive to a bravo one XR,,, and try a 28 or 30 pitch prop to see real gains.... the bravo three will have to much drag over 60 mph....Formula put a Bravo One on those boats that had the 525 or 600sc in them.....just change the lower portion of the drive and install XR gears in the upper

you can't just put XR gears in the upper......and you will still break XR's if your making that much power. A regular bravo is going last even less time. You can change the props but I suggest full XR's for 3 reasons not mentioned. (you could sell the current un-damaged BIII before they explode to offset the costs)

A) The prop selection is much greater
B) They are intended for more speed (which is likely why you built bigger HP)
C) They have more "slip". Which in the case of a big, heavy boat with alot of HP will help your drives live longer.

You should put some arnesons on that thing.

With 700 hp he will eventually......should we take bets on how many bravos get blown up before he does????

B1's or B3's?

I upgraded a a 400 ss about 4 years ago. It had 500 EFI's and Bravo 3 X drives. I added Whipple superchargers with MOAC intercoolers and swapped out the drives to Bravo 1 XRs. It would run upper 60s with 24" Bravo props. He ran it that way for over 2 years and about 80 hrs. He never broke anything and cruised mostly around 4000 RPM. He then decided to upgrade the engines. We rebuilt them with AFR cnc heads and custom cam. They made right at 900 HP on my dyno. At that time we inspected the drives and the gears were beginning to pit, so we rebuilt them. It would run mid 70's with the new engines, low 70's in 100 degree heat and full load, running labbed 26" props turning around 5600-5800 rpm.

Bob Lloyd
Full Throttle Marine

thanks for the input all. i'm only running a couple months on those drives then going to upgrade them this fall. Does anyone know what IMCO Drives would cost??