Top gun 900

Any gurus out there play with imco boxes on a gun I have a 96 with 960hp whipple motors going with scx drives and neg 2 shorties while its apart thinking about boxes a have ran the boat with 840 hp with b max uppers and the neg 2 imco lowers on the transom and no complaints boat was just shy of 90 mph but had endless engine issues last year hopefully all resolved now and new motors also running the 1.3 ratio but can change to 1.5while apart for inspection and shaft changes

frickstyle

I run a 1990 with 5s (surface drive) on boxes set even with the bottom, sometimes run spacers. For all the hassle, I doubt you're going to see much improvement with boxes. Maybe on a different boat / setup it would matter. But your speeds seem pretty good. You may end up gaining 1-2 mph but adversely affect handling or porpoising.

BUT, if you like them and want them for the "cool "factor, by all means! Go for it.

Maybe someone with SCX and boxes can chime in???

cigrocket

iTrader: (3)

I don't think you will see any speed change, and you might end up with a porpoising machine or one that doesn't plane well. If you are looking to spend coin, I would put it into getting the props dialed in. Lots of prop choices these days and tricks to pick up some speed and handling. I think that is money better spent. You already have the notch in the rear transom. So I don't think you will gain anything, The early guns did not have the transom notch. Prop it right and enjoy the boat.

Top gun 900

Thanks guys I will forget about boxes and figure out the best props for this set up been running 16 bravos and 27 five blades bit it wasn't the correct prop yet but goodbstarting piont and it will be different now with more 100 plus more hp and more tq

bencini231

Are you going with the SCX DD lowers or standard -2 SC lowers? Just curious about that since with that hp the SC vertical shaft and the xr gears wont be happy especially with the weight of the 38. I can 100% say they wont last long from expreience and I have drive guardians as well. Go with the full SCX upper and lower to save yourself lots of money now. The SCX DD lower was the best money I've spent to not have to worry about drive issues.

kreed

iTrader: (2)

So you have BMAX drives on it now? You sure the IMCO gimbal housing is a direct bolt on replacement for the BMAX ?

kreed

iTrader: (2)

Always loved this boat. You did a nice job on it. I remember in the beginning you were having engine trouble....you get everything ironed out with the builder?

frickstyle

Yes, he made it right. Spun a main bearing first full year I had it out (2016), then a year or two later I broke a timing chain but no damage to engine. First few years it was rough, lots of teething issues on the build. Since then only issues is with trying to keep transmissions in there. they are maxed out 72C, I think 1350s - just running big props, drives set high and bumpy Lake Erie puts a beating on our equipment. Probably been through 6 or 7 transmissions at least - honestly i lost count it started to become a yearly maintenance item? Both sides. Then there was some structural repair.... I won't get started on that. BUT - everything is new except the fiberglass skin on the boat (original deck coring still there) but all the wood, tanks, any type of hardware imaginable, water lines, fuel line, toilet, etc - is new! Thanks for checking in!

2023 - Cig run @ LOTO (busted a drives shaft and loosened the gimbal - separated from box) - it's always something with older boats.

F-2 Speedy

iTrader: (6)

If the Bmax bolts on the same as a Bravo there will be a helmet change to go to an IMCO

ICDEDPPL

iTrader: (1)

6 or 7 transmissions!? Daum.
Transmissions are the only thing that has never broken, (knock on wood)
The stupid drive guardians are another story.
I also never give it any throttle in reverse, that`s one quick way to fry a trans.Reverse clutches are the weak point otherwise pretty bullet proof.
Also have to make absolutely sure when in forward or reverse the detent is right on, otherwise you`re slipping the clutch and that wont last a day either.