Since my motor is out getting some Schubeck lifters put in, I'm thinking about adding an Imco 12" extension box to my 26 Carrera cat and then trying a 2" short shaft. Anyone tried this combo and what were the results with their cats? Thanks

just spend some of those old guys money from the market and buy a twin engine boat and get it over with see ya

One advantage of a extension box!

I'm anticipating a 10-15mph increase over a standard bravo installation. Notice that I had to have a custom space plate machined so the gimble could slide past the rub rail. This allowed the drive to be set 1" above the bottom of the boat. I also ran the steering lines through the box. It makes the box extremely crouded, but the ease of pulling the box is well worth it. Plus the installation is cleaner. Because of an alignment problem, we had the entire assembly on and off in 1/2 an hour! My stellings box uses a custom inner plate which I highly recommend over the stock merc one. You don't need the steering ram mounts and the drive shaft won't fit through the stock opening so you'll have some sawz-all work to do. The stellings system has no dampening at all, so if that's a criteria, then I'd look at the IMCO system. Their box uses the stock rubber dampener.

JDNCA1, friend of mine has your exact set up. Blown 540 with the IMCO stand-off box and a 2" shorter IMCO lower on a 257 Carrera. The boat runs 100-110 depending on weather and conditions. He put everything on at about the same time, so I really couldn't say what he picked up with just the box or lower unit.

Craig

I'm wondering how the extension box effects the handling of the boat and out of the hole to on plane? I was thinking of jest trying a shorter drive and how that will affect the boat.

What kind of top end speed are you planing to get with your new set up and what were you geting befor? and what kind of powere do you have?

I'm runing 800hp and geting 105mph with 4 people and a cooler.

Well, my goal is to go 100 with 600hp. I "think" the box will make it easier to plane the boat. As the boat starts to out the bow will rise and push the drive into the water deeper reducing blow out. This was a real problem with my old boat. The Bravo prop would slip really nicely. The r's would come up to around 3k, the prop would hook up and then bog the motor back down to 1500 or so. With a Hydromotive prop, it was almost impossible to get on plane. With the hydro though, there was alot more control than with the bravo.

1999 25 Eliminator single step cat
622 ci, 830 dyno hp

DON'T QUOTE ME ON THIS BUT THIS IS WHAT I THINK???

stock drive 99 mph
Imco 2" shortie 106 mph
Imco setback with 3" shortie Imco X-Treme SC 110 mph

give him a call and know for sure 864-287-8565

I'm with Merlin, buy a cat with twins and spend twice as much on upgrades!

Your motor is out and if you have some extra cash I think you should just get it done. You will need to go to dual ram steering, preferably with a hydraulic helm. Then get an IMCO shorty and you should see a 3 to 5 MPH increase over the standard bravo set up you are now running. I will even let you try my shorty as long as Merlin gives us a good deal on the repair if you break it.