IMCO Shorty and Extension Box Help
 

We are making some improvement to our boat and the next step is getting the IMCO shorty and extension box. I just want to make sure I do this correct the first time with the money we are about to spend.

This is going on a 26 Outlaw with a X-dimension of about 15.25". I want to get the most out of the outdrive without sacrificing handling or turning.

I am set on the 2" shorty and was told the IMCO neutral gives a 1" raise. But then I was told I can get a 3" extension box from IMCO as well. I went to their set and could not find one listed. Do they make one? What are some things I should consider and look out for? I don't want to make any mistakes.

Thanks for the help!
Rick

I do not have one but I have done a lot of research on it. I also raised my x dim last year by raising the engine and drive 3".
If you get the standard imco ext box it will actually lower your drive depth by almost 1" because of the angle of your transom.
You could get a 3" raised box and it will raise your propshaft depth by a little over 2". However your engine will have to be raised 3" and your exhaust will have to be adjusted.
The shorties come in -1 or -2 for a standard drive. Most guys with deep drive Baja's have good luck with these.
I am going by memory on this but my it seems my x was 14 1/4" and I raised it to 17 1/4". That equates to a propshaft depth of 8" to 5". With the drive being set back 12" you should be able to run 3" to 4" deep.
Your oudrive should be about 7" deep right now. I have measured a few 25 outlaws and some of the later models were raised to 6.5" at the factory.

If you get a 3" raise Imco box, you also have to raise the engine 3".
I would just try the -2 shorty first without the box.

You most likely do not want your propshaft depth any higher than about 4.5-5". All that will happen is you will get more propslip and less bowlift.

Search Wildcard's posts. Shorty by itself doesn't do much of anything. Extension box works great with good horsepower. WIldcard did the 3" extension box and standard lower. It worked great. He tried a 2" shorty for a total of 5" and it was too much. So, extension box is key. 2"-3" seems to be the magic number.

I would do the neutral box and your 2" shorty to avoid the headache of raising the motor.

What power do you have. If it's stock 496 or 496ho I don't know if you will see anything. Wild card put a 525efi in when he did the box. and then later switched to a 600sci. 500+hp and the gains become very noticeable.

Hey Griff, you always give good advice but I have a 24' Baja with a drive 5" deep. I use a Mirage 25p prop with a lab finnish and double cup. I only have 9.8% slip at 74 MPH. I would think you could go a little higher with the 12" setback. Especially if you used a 4 blade prop.

Guys... thank you for the great replies! :coolcowboy:

I was not aware that the engine also needed to be raised as well... that is not going to be an option.

We are going to have well over 500HP when the engine is all done. So the Neutral Box and 2" Shorty will be the way we go.

Griff, a prop shaft depth of 4.5"-5" is a good target? I want to understand why is this? Because, I have some people telling me I want the shaft level with the keel. This would seem very extreme to me. I want to get the most out the boat but I do not want to sacrifice the basic handling abilities.

Thanks again everyone for taking the time to help! :drink:



jeffswav, do you boat on the Kaskaskia River? If so, we'll have to meet up one day for a run.

Yea, you have a 26 Outlaw. Does it have red a black graphics? We go there quite a bit, its only 30min from my house. We go to Kinkaid a couple times and take a big trip to Norfork once a year. I think we are going to try Rend lake this year also.

If you aim for the p/s level w/bottom.

1. You'll never get it on plane ( unless you use a 6 blade prop)

2. If you somehow were able to get it on plane, you
wouldnt have any trim leverage ( which you need
on a regular V hull)

I tried a set of 2" shorties on my boat ( which the drive
height is 3" below the bottom of the boat) and could
not get it on plane (and that was with 5 blades, and boxes)

You could do a Stellings box and raise the drive up without moving the engine. You can set it at 0, +1 or +2, you would have a drive shaft with u-joints instead of the shaft with coupler. I think that is what Griff uses.

That was us, the red and black 26 was our old one.

We certainly boat on the same bodies of water. We love Norfork and enjoy a trip or two to Kinkaid.

JaayTeee, thanks for the good information!

I am going to go with the neutral and 2" shorty like I had originally planned on doing.