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Discussion Starter #1
Okay, hopefully you guys wontblast me too bad for asking dumb questions but here it goes:

I bought a 85 k10 suburban - 350 / 400? / ????transfer case with 12"-16" of lift and 39.5" TSL's from a seller that was VERY motivated. The lift is nearly impossible to measure since it is a combination of addleafs and blocks.

I wouldlike to start a thread to get advice from some of you more experienced guys(and gals) so that I don't have to learn many lessons the hard way.

There aren't many rock trails down here, so my primary use willl be mud.

My first concern is the 1/2 ton axles&housings under the truck. they are the 14 bolt 6 lug originals (44's?). What is a good quality inexpensive option for upgrades/swaps?

Next I need to replace ans upgrade the transfer case - any suggestions?

HELP PLEASE!!!!
 

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If they are the original axles you don't have 14 bolts in a K10...you have a 12bolt rear and a 10bolt front.

Cheap upgrade would be a 14bolt FF for the rear and try to find a 10 bolt from a 1989 to 91 Suburban 3/4 ton for the front, they have 30 spline axles.

14bolt ff will be 8 lugs so you will need the front axle from a 3/4 ton suburban if you want 8 lug fronts also.

The best upgrade you could do is 14bolt ff rear and a dana 60 front but plan on paying about $1000 for the dana 60...running 44's that would be the smart move, I don't know how long your current axles will last with that big of tires but my best guess would be not long!

Why do you need to replace the transfer case? You should have an NP208 T-case right now and they are fairly strong, however if you are looking for a stronger one then upgrade to a NP205.
 

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Discussion Starter #3
Thanks! there's a swap meet next weekend, and I'll start looking for the axle parts. The auto hubs were still on the old axles(pieces of them) and I switched them out yesterday for MM premiums - just to give you an idea about what I've got to work with here.

I am concerned about the T-case because the current one is not in very good shape. It jumps out of 4H while I'm running between trails, and it bleeds fluid like its been stabbed. I'm just trying to get it solid before I try to get stoopid with it. I'll plan a rebuild for that to go with motor and tranny later.

BTW -anybody ever seen an "OMC" 350. Outboard Motor Company----I've been told that it never had alot of power but that the bottom end is VERY Solid. I wonder if I can get by with machining the heads and still be good?
 

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So what are you trying to do?? Mudder, Mudder/DD?? First off you gotta find out what you really have for a engine, tranny, and t-case first. If your gonna run 39.5's you want at least 1ton axles. Also gearing is gonna be a major factor on turning those big meats. I'd almost say rockwells to get the ratio.
 

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if the engine is original there should be a "spid" label somewhere with a bunch of 3 digit/letter codes. most likely the glove box. that or your engine code is the 8th digit of the vin. K being a 350 for your year. as for trans & T case it sounds like it may have a np 208 in it. theres a red & silver tag on the housing that should have numbers stamped in it. that is what tell you for sure.
 

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turbo 400 pan ^



th 350 pan. should help I d which one you have.
 

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Discussion Starter #7
Right now I am seeking advice to make it a more solid toy - cheap. I know that stock 1/2ton axles are like tooth pics when attatched to a 85+ pound tire. So that seemed like the best place to spend my money first. The gear swap is a great idea - 4:10's or should I dig for something bigger?

I'm trying to get it into shape to have a weekend toy for some less demanding trails. This is a new hobby, so prying $$$$ out of the wife is like .... well we all know. The truck still street legal right now but I have no intentions of making it a daily driver, just something for us to tear up and fix(hopefully not too often). I can trailer it when needed.

I just bought this truck from a college kid so that I would have something to work on wih my 11&13 year old sons. The engine is a project for later, I'm just currious if there is a reason that he put a boat motor in this truck.

When I FINISH---a couple of years down the road I want to be running BB chevy, a 2 spd power glide - rockwells and 44+'s.
 

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Go to the axle tech forum and there's a chart in there that will tell you what gears you should run. 4.10's are far away from what you want!!! Power glide is not what you want for a tranny you want and TH400 or TH350. Right now if you want rocks just get them know and same some time. You can find them for 1200 a pair or so. I got my Dana 60 on a steal of a deal. But there getting few and far between!!
 

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A couple of things.

With 39 inch tires you'll probably be happy with the lowest gears your axles will fit. This depends on the axles you are planning to run, Rockwells are neat, but you can't beat a good ol set of one tons. If you run a low pinion 60 front and a low pinion 70 rear, you can go down to 7.17 gears, which is lower than Rockwells.

As for your question about the OMC boat motor. The short block is identical to a pickup truck 350 engine. Nothing special there. Also, beware of boat engines that ran raw water through them, they tend to rust out from the inside.

Also, if the engine came from a boat, make sure it is the right rotation for your truck. Boats commonly use reverse rotation motors. The cam will be different, as well as external components. Frankly, I'd stay away from marine motors. I've attempted to use them in the past, and the cores end up being junked.

You mention the lift is a mixture of blocks and leafs. If it has front blocks, get rid of them.

And you also mention the truck being eventually done. It will never be done. If you really get into this, you'll find you are always changing and upgrading your rig. Welcome to the world of busted knuckles and being broke!
 

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A couple of things.

With 39 inch tires you'll probably be happy with the lowest gears your axles will fit. This depends on the axles you are planning to run, Rockwells are neat, but you can't beat a good ol set of one tons. If you run a low pinion 60 front and a low pinion 70 rear, you can go down to 7.17 gears, which is lower than Rockwells.

As for your question about the OMC boat motor. The short block is identical to a pickup truck 350 engine. Nothing special there. Also, beware of boat engines that ran raw water through them, they tend to rust out from the inside.

Also, if the engine came from a boat, make sure it is the right rotation for your truck. Boats commonly use reverse rotation motors. The cam will be different, as well as external components. Frankly, I'd stay away from marine motors. I've attempted to use them in the past, and the cores end up being junked.

You mention the lift is a mixture of blocks and leafs. If it has front blocks, get rid of them.

And you also mention the truck being eventually done. It will never be done. If you really get into this, you'll find you are always changing and upgrading your rig. Welcome to the world of busted knuckles and being broke!


X2

[/COLOR
How much money you wanna spend putting 7.17 in those though, bye the time ya buy them and then turn & buy r&p's. That's more money than you would spend on rockwells!!
 

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A couple of things.

With 39 inch tires you'll probably be happy with the lowest gears your axles will fit. This depends on the axles you are planning to run, Rockwells are neat, but you can't beat a good ol set of one tons. If you run a low pinion 60 front and a low pinion 70 rear, you can go down to 7.17 gears, which is lower than Rockwells.

As for your question about the OMC boat motor. The short block is identical to a pickup truck 350 engine. Nothing special there. Also, beware of boat engines that ran raw water through them, they tend to rust out from the inside.

Also, if the engine came from a boat, make sure it is the right rotation for your truck. Boats commonly use reverse rotation motors. The cam will be different, as well as external components. Frankly, I'd stay away from marine motors. I've attempted to use them in the past, and the cores end up being junked.

You mention the lift is a mixture of blocks and leafs. If it has front blocks, get rid of them.

And you also mention the truck being eventually done. It will never be done. If you really get into this, you'll find you are always changing and upgrading your rig. Welcome to the world of busted knuckles and being broke!
X2



How much money you wanna spend putting 7.17 in those though, bye the time ya buy them and then turn & buy r&p's!! It's gonna cost more than rockwells then!
 

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Discussion Starter #12
Found a pair of rockwells for $700, Front has had 71/2" cut off of long side so that short drive shaft will fit either side and it is the same length as the rear. They have 6:17 gears in them....I think this is pretty much perfect for my project - anyone disagree?
 

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Found a pair of rockwells for $700, Front has had 71/2" cut off of long side so that short drive shaft will fit either side and it is the same length as the rear. They have 6:17 gears in them....I think this is pretty much perfect for my project - anyone disagree?
What? Stock gear is 6.72 in rockwells!
 
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