berns29scarab

as anyone put shorties on a 353 ? spoke with a local shop the other day and they said they had a 99 or a 00 353 with 500hp's and installed 2" shorties and hydro PX5's unsure of pitch and picked up 8 mph on GPS...can anyone verify such an increase ?

Rippem

well I know the standard X was moved up sometime in '00, so that would tell you the 98-99's could stand to have props closer to the surface. On this boat with boxes tho, arent they already high on that hull? Are the boxes neutral? Or mounted in the "one up" position?

berns29scarab

unsure of the current x-dimension but i believe the boxes put the drives deeper, i know 1 thing...coming up on plane no tabs and drives at a full tuck nose comes up fairly high, no cavatation, drags for a few then pops outta the water. 1st time i ever ran the boat, and the current owner has no specific settings marked on drive or tab indicators...i'll have to tinker in the spring

Magicfloat

Seriously doubt it. And the cost to try it would be high if it doesn't work. You might try raising the boxes,there are 3 holes to vary height. Formula normally uses the middle hole. And,BTW,boxes raise the drives,that is the whole point. When you move them back,you can move them up. Old bassboat technology from the mid 70's (jackplates)

berns29scarab

how can i tell what brand boxes are on the boat ? i've never had a boat with boxes and a buddy says take them off cause they hurt the drives due to not have the rubber isolater ? supposedly to diff styles of drive shafts some are direct and others have a couple ? this is new to me dont mean to sound like a dummy..

FormulaM2Formula

My '01 382 w/ HP500EFI's and XZ drives came from the factory without stellings boxes and they were added later by the previous owner. The shop doing the work did not raise the engines or the drives. The boat had a terrific hole shot but seemed a little slower than other 382's with this setup.

I talked to Formula about the situation. They said that the drive height was 2" higher on a factory boat with boxes than without boxes. One of my XZ drives grenaded this past April. I had new drives built with XR upper units and 2" shortie IMCO lower units with XR internals by Mr Gadget (Dick Tryce.) Dick does some internal mods to the drives and his prices are reasonable.

I now have ~25 hours on the drives. Here are my observations so far.
1) I can not tell any significant difference in holeshot. The trim limit spacers in the drive were changed so that the drives tuck in more in the full in position.

2) Now that I have some time on the drives, the boat seems to have picked up 1 or 2 mph and has on occasion been as much as 4.5 mph faster under some pretty ideal conditions. Unfortuantely, I wouldn't call any of this very scientific. The more hydrodynamic shape of the IMCO lower may also be contributing as well as having less drive in the water.

3) BUT, a lot of folks say that the XR drives have more internal HP loss. So, to have picked up a couple MPH, and have a more heavy duty drive, and the cool factor of IMCO lowers, it all worked out as a positive.

4) The boat seems to ride a little bit flatter at speed too, but maybe this is just my imagination.

Keep in mind that the drives on my boat were 2" lower than Formula would have set them had it been a "factory" setup which is why I wasn't afraid to go this route. So, I don't know what would happen on a boat that already had the factory specified drive height setting.

My stellings boxes could be raised another 2" and I'd like to try it. But, I doubt I do until I build a shop in my backyard. I don't see anyone working on the shop, so it might be a while.

I wonder if anyone has tried going from stock Bravo 1 X lowers to IMCO lowers and know what speed they picked up. Intuitively, it would seem IMCO lowers would help. So many things changed at once on my boat that I can't really say it was any one thing.

Garrett