Which is better ? Raising the "X" dimension with an extension box (3") or 2" shorter lower ? I know the 2" shortie would be easy to install, but which would do more in raising speed and better handling?
I currenty run a 251 convinsor (Checkmate) with a 468 Big block/ Bravo 1, at 80mph. Which way should I go ? What's everybodys opinion?

Probably both?? The short drive may work even better on a box. I know Checkmate installed a lot of their boats with the drive mounted higher than a lot of other Mfg. The short drive may not work without a box. The only real way to know is to give it a shot. Be a pioneer and let us know how it works!!! Good luck!

A friend put the -2 on a 261 Check and I was told it didnt handle the rough water as good, couldnt keep the bow up during wave to wave action. The stand off will give you more leverage to hold it up and the -2 would raise the drive almost enough. They say up 3" with a 12" box. I installed a box on mine when new and moved the whole thing up at least 3".. 283 Check Convincer..

Good luck

Dick

the rule of thumb is to keep your CG as low as possible,have used a combinatin of both and it did work well.....but the exstension boxes were created before the shortie drives to be able to raise you X dimension,evey boat is different and would try to use the shortie drive first,if somebody had trouble with the 2" than a 1" would be my suggestion.him saying it didnt handle as well in rough water is kinda wierd as your trying to loosen the boat from the water and cut back drag.......now of course when you run an extension box youll be raising the height more but the water leaving the rear of your hull is trying to head upward,which requires the drive to be higher to keep the drive from being to deep creating more drag......

just wanna let you know, we are running a 2" shortie with the 3 " offset box on a 28 pantera. still a bit too soon to tell you a whole lot. but i will tell you this. the boat handles great. as far as more speed , we are still toying with it. so i will keep ya posted. best thing to do start with the 2 " shortie. see how that works. if you feel like your getting on plane easily and you see more speed, then maybe the box would be good for you. but remember, you have to raise your motor and cut your exhaust holes higher.

good luck

Thanks for the reply's , keep the ideas coming. I think that the logical approx would be the "shortie"First, But I don't know if I need both ? Handling is a big part of the solution.

Bruce, why would you need to raise the motor for the box ? Looking at Imco's does this require raising the motor ?

dlbCheckmate,

When you install a box, typically the drive should go up 3" because it is back further. When the drive goes up.. the motor must be in line. Now the stellings box uses a drive shaft and you can adjust the box up and down, maybe an inch, without moving the motor. Other wise you have to raise the motor.. Hope that makes sense..

With the Imco box the input shaft on the drive needs to be replaced with a longer one. It is a torsion type of shaft to help take up shock. Also with the Imco you use the coupler, giving you a bit more flex in the drive line. The stellings box with the drive shaft bolts right to the crank flange. There are pros and cons with each type box. I have the Imco.. simple, non adjustable. I havent broken a drive yet, so I cant tell if it is working or not.. Just havent beat it that hard yet..

Good luck

Dick

dblCheckmate

with the three inch raised box, you change the height of the drive, thus changing the centerline of your shaft, therefore you have to raise your motor as well. possibly requiring exhaust modifications as well or at least relocating your thru hull cut outs