388 Slingshot w/ Imco lowers -- Extension boxes?
 

Who's running lowers on their Slinshot? Standard, -1, -2? Just finished all my winter projects. Starting to make plans for next time around. Thinking about extension boxes as well.

Running mid 90's right now with stock XR's. I've read all the info and understand the boat wasnt designed to run that fast. It definitely gets loose in back once you get in the 80's. Talked to a guy at the shop that said they put a set of Imco's on a sllinshot and the boat drove a lot better, like it was on rails. Makes sense. I'm sure the pointed leading edge would get more water across the props which should settle it down.

Almost feels like the back end is moving sided to side. Would like to get her tracking straight.

Just looking for others experience.....

I have a 2003 388 with 575's, extension boxes, XR uppers and imco -2 shorties. I do not have any experience driving a slingshot with any other set up but I have seen mid 90's and the boat handles good. I am not sure I would say "on rails" but with proper trim and tab location depending on water condition, the boat tracks nice.
hope this helps.

We had a 2000 Slingshot with Stelling ext boxes and XR drives. Replace them with Imco SCs. Tried -1, then had to put spacers back in. We tried all sorts of props, but the original tweeked 4 blade Mercs handled the best and were the fastest. Best of 102 and still more left, just ran out of room. Tried other 4 blades and had Hydro P5s also. We also turned the props in to keep the back down and ran the extended 380 tabs.
The Slingshot is a great boat, just gets a lil interesting above the 90 mph range. Very fast with smaller power. Good luck with the projects. They are fun.

rock solid
 

1999 with 750+HP 572ci na's ran 102 with 1.5 xr's @ 5400rpm stelling boxes 5 blades 32p herrings spinning in or out ABSOLUTLY NO handling issues rock solid straight as an arrow right too 102 mph... but spin in it's faster by 2 ticks....
currently running 1:1.3 B-Max HT's and 95-97 mph.

I we also tried shorty's no success. just makes for a very expensive blender ;)

It's listed in the hustler section.
hope this helps

Im in the same boat. I've got a 99 with 720 na 565's I replaced the xr with tcm platinum xr with imco -2 without boxes and have had hell was told that 32 herrings would be best but it takes forever to plane then all I see is 88 to 99 but only turning around 4800 to 4900 motors really need to be turning 5400 to 5600 I only achieved these numbers after installing 1.5 spacers. Kind of stumped as to where to go now

Rob
Do you have any suggestions to throw in. I was thinking of shorter lowers but sounds like standard lower may be best. I have no intention of adding boxes, would Imco or sportmaster lowers help?

NEVERSATISFIED,

I ran a 2000 388 with whippled 500EFI's for 3 years, 5 blade 32" Hering's with flared diffusser ring cut of and 3" extension welded in by factory. Drives were factory mounted location.Turning in best I ever seen was about 98.7 on gps.You had to drive thru the walk at over 92 then it settled down.In the fourth year for the hell of it we installed 2" spacers, we hit 102.3 first time out, no more walk or loose back end. You just have to keep at it till you find the sweet spot.

P Rob

Was that with standard lowers?

Yes on the standard lowers, 1.50 gear

Could I expect to see any speed increases or increased stability with the standard sportmaster or Imco lower