socalstone

Yeah, CMI has that set of headers for the 496ho that are good for almost 60hp right out of the box. Probably sound better too.

AIR TIME

HOW MANY INCHES IS YOUR DRIVE FROM THE KEEL CENTERLINE MINE WAS 7'' AND WITH THE 2'' SHORTIE IS 5 WHICH MAKES MINE RUN NICE HITTING 83GPS ,I need abigger prop should hit 85 to 86 when its done wild card has a 3'' built into the box from imco stock drive. from what I read. art

EdNewman

Doc, I spend the day with a race rigger today and I am going to go with 2" shorter IMCOs. I am a little worried after your experience, but it also leaves me with a few questions...

1. What do you mean you don't have cavitation plates? The IMCO's use a stainless steel cavitation plate that bolts on to the back like the Merc sportmasters. If you did not have this, it could be part of your problem.

2. What did you do with the props? I was told it is very important to add some "cup" to the props when running shorties. They basically angle the last 1/4" of the prop blades up by 30 deg.

JasonSmith

Not to jump in before Doc, but I run 3" shorties on my 29 Outlaw, but I have 12" extension boxes also. I had 1" on before the boxes.
The best way to describe what will probably happen is you will experience a ton of slip comming on plane from appx. 2000 rpm to 4000 rpm, but it will not be enough to keep you from getting on plane. Mine did it with the 1's & with the 3's.
Once the boat comes over on plane it will bring the rpms right back down.
I wouldn't worry about it at all. Run the propellers as they are 1st, then tweak them if you think it needs it, but I doubt it will.
Doc, your turn.

Dock Holiday

It becomes a center of gravity issue. The two 36 Outlaws that I know of running 1 inch shorties do not have A/C. I do and that the only main difference. One has big power with Whipples and I really do not believe that he has gained anything more with the shorties then he would have seen just with the Whipples. The other boat is still trying props and is living with the difficulties getting on plane.

To answer question #1, YES I had the stainless cavitation plate that bolts on. But you loose the larger one off the lower unit that is much more effective on the Baja.

As for props I tried the 30 pitch Bravo's that I had been running before the change, I tried some 28 pitch Bravo's and also some 28 Pitch Hydromotive P5X 5 blades.

They all planed very slow, the five blades did well at cruise but I lost top end speed with all the props from between 2 to 5 MPH.

I then added 1 inch spacers and it helped slightly, but not worth it overall in my opinion.

Baja told me that I would not like them. They said I would have to power through getting on plane and they were 100% correct. This is no fun, and it is very hard on your outdrives.

With extension boxes they probably would plane better and be closer to stock performance, but it is not worth the expense in my opinion for the maybe 2 MPH gain you may see.

I would be VERY surprised if you could even get on plane with two inch shorties. I'm sure my boat would not after trying the 1 inch.

My guess is that if you put enough cup in the props to get on plane easy that it would greatly effect top end.

We ran a poker run last weekend with the original drives back on the boat and it was NICE. I tried them and wish I had not wasted my time nor money.

I have a set of IMCO inch inch shorties satin finish with 1.5 ratio for sale. New they were $6800.00 for the pair and I'll sell them for $5400.00 / pair and pay the freight charges if anyone wants them. They only have 8 hours on them.

Dock Holiday

Yes and No.

I agree with your above statements Jason, however you are trying this on a 29 versus a 34 or a 36. If we all have the same engines and drives, then you will get more leverage to get the bow up.

I have A/C and I bet the 342 does also. That with the extra length and there is a big difference.

I was told by a guy in the know that if you have extra people on board riding in the back seat and your boat runs faster with them then without that your center of gravity is off. He has actually added weight in the engine compartment and picked up speed. My 36 was not like this until I added the shorties, and then my boat ran better with more people. You have to get the drive down and the bow up. It is MUCH harder to do with shorties alone.

Personally I would bet that with just two inch shorties and no extension boxes on a 342 that it would not get on plane.

JasonSmith

I have to disagree that the slip is hard on drives. My thought is, and I could be wrong, that the drive never comes "unloaded" so there is no shock to the gears. If there is no shock to the gears then there shouldn't be a problem.
Another way to look at it is like a burn out in a car. Lots of slip, but no big bang like airing out.
Mabey I'm wrong?
I do agree with the fact that my setup is wierd & I also think that I would have the same speed up top without the extension boxes or 3" shorties. My thought is that the extension boxes make the 3" shorties work. If I had not gotten the deal on the 3" drives I would not have went with them.
Oh, that & they look soooooo cool! Who cares if it is fast!?

EdNewman

The factory setup works exactly how it should. Deep X means easy to come on plane, easy to turn but it takes lots of trim to get the boat up to speed. In terms of stressing the drives, I look at how much trim the stock config takes on the 36 and I am amazed we have not seen more blown universals. Doc, you are running all on fresh correct? I wonder how much of a difference salt would make due to the bouyancy. I do have A/C in the boat, but can't imagine it making that big of a difference. When I was looking for this boat, I almost bought a Formula and when you talk about having to work it to get on plane... it was extremely hard to get up. Maybe we are just spoiled. I guess time will tell. I will keep you all posted in about two weeks.

Dock Holiday

Good luck and keep us posted.

Dock Holiday

I have TWO IMCO one inch shortie lowers for sale.

These have exactly 8 hours on them, they are low water pick up, satin finish, 1.5 to 1 ratio, XR series BIG SHAFT.

I bought them brand new in December 2006 for $3400.00 each and installed them on a 36 Outlaw which was ran the first time in March 2007. My boat does not like them, it is too hard getting on plane.

They were filled new with Royal Purple gear oil and the oil was changed at 5 hours per the suggestion of my drive builder.

These are in perfect condition. My lose is your gain.

$5400.00 per the set, or I will split at $2800.00 each for single.

All shipping paid in lower 48 states via UPS Ground and insured.

I accept VISA, Mastercard & American Express.

Note that IMCO has no warranty on their drives. I bought them without warranty and cannot offer any warranty. These units performed perfectly and are not damaged in any way. All sales are final.

These come with the stainless steel cavation plate as provided by IMCO.

Send me a PM if interested.