Extention Boxes on a 42 Fountain?
 

I am considering several winter upgrades. Last night at one of our beer and boat bench racing sessions my friend suggested maybe trying boxes. I have triple 600's on bravos, what would I expect as a result of the installation. I really am seeking more top speed. What do you guys think it will do for the boat? Midnight:cool:

I think Boxes are good, but it is usually best to have them installed when you are moving the X demension. I'm quite sure that your 42'Ftn has a notched transom which would allow you to move your X dem even higher. Of course you can also buy some IMCO or Merc 2" shorter lowers to help offset this. Obviously, you want the installation to be installed in the most advantageous spot or X dem. This may also mean raising the heigth of the engines. You'll have to decide whether or not you are going to use the 2" shorter lowers or not in the very begining and work from there. Extension boxes will artificially increase the length of your boat, make it handle/trim better and may give you a speed increase of MAYBE 2mph. It will require a TON of work so be ready and willing to lay down the SMACK!

Saber Marine in Coopersville did my 32'A/T a couple of years ago. My A/T originally had TRS drives w/transmissions and I wanted to go with a more updated drive package (Bravo Ones) and I knew that if I was going to install some extension boxes that would be the time to do it. We had to fill in the transom find the X dems and recut, and we mounted mine as high as we could install them which was just underneath the rub rail. I used the Stellings boxes---of course there are other brands on the market with other options.

Saber Marine did an excellent job on the project and I have found that they are highly competitive. I would highly recommend them. They have done several drive installation projects. In fact, I think "Check300" just had the heigth adjusted on his #6 drive by Saber Marine. If you're going to do it you had better get at it now or at least get yourself in line cuz there's more work involved than you think. Saber Marine's number is: 837-6442 ask for Jim. Best wishes
Mark/KAAMA

While we had the engines out of the boat and knew that they would be relocated, I went ahead and had the IMCO boxes with their steering system installed.
As KAMMA said, its costly...Parts and labor were almost $10K for twins.
We left the X dim pretty much alone, went with the neutral set back boxes and the -2 lowers.
You might pick up some mph just by having the nose cones thats on the IMCO's...hear that they like 90+
You might just want to get some -1 IMCO lowers and save the cash for the motors.

So you feel it may be money better spent to install IMCO shortys. What do they cost and what speed increase may I see? Midnight

I have a 42 R & D boat that has triples. if you want to go with extension boxes go with imco. but is 3 to 5 mph top end worth it. I do not know. Boxes and steering with labor is going to run you close to 15 to 18k.
We are in the middle of rerigging my 42 for the 2nd time with triple 850's no cabin and skater interior. But is estimated tol run over 120mph if you want to compare notes email me and I will let you see everything we have tried.
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Imco neutral set back with -2 SC's