Hi guys, I'm new to the forum. Have a question about swapping the lower gearcases on my Bravo 1's.

The boat is a 1989 IMP 310 Eleganza with twin 454 Mags (365 hp). I am running 25 pitch 3 blade SS props and right now the boat tops out at 64mph (GPS) at about 5100 rpm.

I have been told that my Bravo's will never go faster than 70mph because they are early versions and will "blow out" water away from the props. And, that they could be holding the boat back even though it isnt running 70mph. Would swapping to newer style lowers gain much if any top speed?

I appreciate any opinions or advise... Scott

If you were at the 70 mph threshold it might, but your
6 mph from it.

I will possibly be supercharging the engines in the future and am just trying to get my ducks in a row first. I do realize the engines will most likely need to be gone through when i do the superchargers and i havent even dicided if i will go with a Procharger, Weiand 6-71, or Weiand 177... Just trying to get my facts straight so i can budget enough money. If my drive style is going to limit top speed i just want to be ready to replace them. I have read and been told that the Bravo's are good to approx 600hp so i will be staying under that hp... Thanks...

The older style lowers don't usually have the oil passages that the newer ones do. So you can't just swap them. You can plug the oil passage, but depending on how many hours are on them, you would be better off buying a newer set of drives. The oldest you should consider would begin with OM in the serial number, which indicates the thick floored gears. With the roots style blower, you will still be stressing the helical gears.. Prochargers are a bit more forgiving in the drive dept..
Hope that helps.. Best save up a large stack of money, you are into boating now!!

PS. I had a 251 Checkmate that hit a wall at 78mph with the short lower. A Hydromotive nose cone took that beyond those numbers to high 80's.

Dick

Thank you for the info... I really appreciate it... I figure its gonna be much cheaper and more satisfying to take an older boat and "spruce" her up a bit vs spending upwards of $200K on a newer one to essentially accomplish the same thing - "LOOK GOOD & GO FAST"...