I would be a gunner on the 1/2 spacers.

Hawkeye did a 2000 with 500EFI's and stellings boxes,
I asked Jeff how it was set up, here is what he recalls,
if this is any help.

"The actual hull was different (in size / depth), however the hull / strake design was very similar. The 342 w/ 500 EFI's that we had was raised 2" above Baja's Standard X Dimension and we used Stelling adjustable (3") boxes. We ended up raising the boxes up another 1". I don't recall what the standard X Dimension was back then, but then again Baja's seemed to vary with in 1/2" from one to another, so it would be hard to say what standard was. We were running Mercury 30 Pitch Lab props w/ Baja tip cut. Our boat had full cabin amenities and ran 82 MPH. We did another one with out boxes and that boat ran a consistent 80 MPH."

Keith,
Did you get it dialed in yet ?

Yeah, I have it at 77-78MPH GPS @ 5200 right now. Took off the IMCO's and have the extension boxes at the middle hole with stock lowers. The problem was the 496 Mag HO knock sensors were so sensitive they were picking up the universals in the extension boxes. Had stage 2 programming done to the ECM's and and it slightly reduced the sensitivity on the knock sensors and that was 90% of the problem - it was retarding the timing 20 degrees with a huge loss of power. We figured it all out after we put the engines on the Mercury computer. I might even move them (stellings) up to the first hole before November if I feel like the miserable 6 hour job.

Yeah you can they are alive and well in Bucyrus and on this site.

XT Innovations

Dave, Adam & Lane with over 60 years of experience.

Plus right now they are working out of the back of the Checkmate factory where Doug Smith and Dean Reynolds are in charge.

If they cannot answer your question it cannot be answered.

The boxes did not work well on the 36 Outlaw. I tried shortie lowers but did not have enough horsepower to make them work on the 36.

Great to hear,
Sounds like you're making progress with it.

Have you checked the u-joints for being in phase ?
( the yokes at each end are suppose to be aligned
with each other)

Mine weren't.
When you would rev it up in neutral, it would
vibrate as if you had the drives raised to the full up
position.

I corrected it, vibration is gone.

If you do move them up, let us know how it works.

I've heard mixed stories about running them in the
highest position, due to shaft angle, I've never
got a good answer about it.

Good info. Sounds like the imco units perform exactly like the Merc units at speeds under 90. With the stock lowers, that extra inch up should help considerably, assuming your not having any problems with blow out getting up on plane in the current configuration.

What year is your 342?

Keith,

What did you do to the 496's to get them to 525hp?

Keith

2003 - 342

I need to move the boxes up another inch and maybe try the 1/2 inch spacer plate. 4 blade props with no blow out at all so I am thinking about 3 blade mirage plus if they hook up. I have virtually no blow out at all when coming up on plane.

496 HO was the base and upgraded to Crockett CNC heads with big valves, Stainless Marine Exhaust Manifolds, fuel pressure at 50 PSI, Raylar 103 cam (not quite radical enough) The combo was supposed to be 525 but realistically I think around 490 +/- maybe 500 if the stars align.

I need to get the boxes up and I can get a few more out of it and better props for another few. I hope to get it over 80 by next summer.