Benefits of an Ext Box ?
#31
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I gotta say that the only way an extension box works on a Baja is to raise the x dimension. There are 3 ways to do that. Listed in my preference.
1) +3" Imco box
2) Stellings box with -2" shorty.
3) Neutral Imco box with a -2" shorty lower or -3" drive package.
I would suspect the 25 that Doc drove had a stock length lower with a deep x dimension. That combination would indeed make the boat slow & enable it to carry the nose to excess.
Setup is the key. You need to know where you are at on the x dimension 1st.
1) +3" Imco box
2) Stellings box with -2" shorty.
3) Neutral Imco box with a -2" shorty lower or -3" drive package.
I would suspect the 25 that Doc drove had a stock length lower with a deep x dimension. That combination would indeed make the boat slow & enable it to carry the nose to excess.
Setup is the key. You need to know where you are at on the x dimension 1st.
If you truly need a full 3", then consider a neutral IMCO box, a 3" IMCO shortie and an IMCO upper (required when using a 3" IMCO shortie because of the cav plate). Look at the upside, you end up NOT re-rigging your motor mounts and have a much better upper drive section. It's only money.
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nope same motor 509 picked up between 13 to 20 hp thats it with the custom carb but it ran better on top, so we figured 4 to 5 on shortie and 3 to 4 on carb change which might be high. this was multi runs over a few weeks. other power was 330 to 390,585,595,637,647, aprox 670ish in the end, but will get a few adjustments to get it over 700hp intake cam carb change, ne motor 572 blower but might be going in a saber 28 or sutphen 30. this spring.
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I am going to add the Stellings Box and 2" shorty on the off season. I would love to pick up 4-5 MPH with the mods but am not so certain it will happen. I hope at the very least to go taller in prop size to net a few MPH but again, not to certain it will happen. All this is on a stock 496 HO that can do 63 MPH GPS all day with either a 24P Bravo 1 and a 23P M+.
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I am going to add the Stellings Box and 2" shorty on the off season. I would love to pick up 4-5 MPH with the mods but am not so certain it will happen. I hope at the very least to go taller in prop size to net a few MPH but again, not to certain it will happen. All this is on a stock 496 HO that can do 63 MPH GPS all day with either a 24P Bravo 1 and a 23P M+.
Last edited by AIR TIME; 10-18-2009 at 08:13 PM.
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for the guys that have stock exhaust and want more speed a set of headers or stainless marine and the 3'' box is the way to go, just do the box 1st and have the exhaust co send a template for you to get your angles so theres no transom holes to change, and theres a lot more in the bajas. I have seen room to go up the few inches on the front of the motor and then you can play more with a shortie if you want but after our friend over sea's posted a 3'' box with a 1'' shortie total of 4'' shorter was perfect for his 25ol with the merc 600 last I heard he was running 87 88 not done yet. but with the 3 inch raised box he got 81 mph from 74 to 76 with a 28 b1 prop once he put the 600 merc in he put a raised shortie 2'' imco on then lowered a1'' to be at 4'' total at 87 plus
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If you use the Everett Performance shaft it is great. It is a slide on shaft. You dont have to change your yoke. You can keep your coupler and wont have to remove the bellhousing. It is $550 new and supposedly works better than the IMCO set up - Randy at Stellings told me that.
You will not have to reprogram the ECU either...
I have a great line on a Stellings neutral box and IMCO steering that I am going forward with. Just have to find the 2" shorty to complete the project. I do want to add the new CMI e-tops but it may not be this off season.