Will 49'' Iroks fit on my 1983 Chevy K10 1/2 ton if I put 14'' of lift on it. What gears should i run? it is a daily driver and a dunning/mud bogger.  

You need to trash the axles front and rear and get some Dana 60's at minimum(front and rear and they are marginal for this but much better than stock). A GM 14bolt corp is out because it cannot be geared deep enough.  As far as gearing, somewhere around a 6.14 to 1 or deeper should work (though you should be in high 6's or low 7's in axle ratio with 49's). A 4.56 or 5.13's will not cut it with tires that big.  

I agree with snoman's gearing advice, but I think a Dana 70 rear would be a better choice.  They're rather common, too.  You can find one under 1 ton duallies and some crew cab single-wheeled trucks.  49's are heavy tires; you need all the axle strength you can get.

I did say that the 60 was marginal for those tires. There is not much to be gained in axle strenght with a 70 as a 60 can be upgraded to larger axles though a 70 would be nice if you could find one and a 80 would be better yet. If driven somewhat conservatily and with a automatic, 60's should workout fine. Driven hard and with lockers even a 70 would have problems.  

two words

rock wells

Yes Rockwell's were in the back of my mind but when you move up to those, a lot of things change then not to mention you add well over 1200lbs to your weight and fuel mileage goes from bad to down right poor. I would still say 60's as there are gear ratios availible for them up to 7.17 but not for 70's. Use after market axles in them and they will be strong enough for reasonable use and a lot lighter than rockwells.  

MPG?  How 'bout GPM?  Does a person with 49's really expect decent MPG?  I'd say Rockwell's would be the way to go.  Not only are they bullet prove (literally), but with all that weight that you insist is bad, you lower your center of gravity. 

Naw still MPG not quite GPM yet and at 2+ a gallon and climbing you must consider everthing.  The extra weight is not nice to have in the mud, level or uphill and ups HP requirement of vechical to offset extra weight ant it also makes it a lot tuffer to extract when you do get stuck with the big Rockwell anchors in mud. No thanks, you need to keep weight factor is equation unless it is just for show or jumping and crushing cars.  

Im only 13 and not if you have low 7 or 6 axles duh do u like the four wheeler mag 'cause i do

i have to agree with jason on this one.  if you're looking for MPG, go with a suzuki or something much lighter to begin with.  you could run dana 44's and your gas mileage is still gonna suck.  1 ton gear with 44's will cut it, but it hasn't been overly tested with 49's.  rockwells do weigh more, but the benefits are a lot better that some extra pounds. 

do it right the first time because once you start breakin stuff, you'll wish you did.

We are not talking about a Suzuki here. 60's with after market axles will work fine unless you get very extreme and cost a lot less too.(I think the housing will fail before after market axle will when pushed to limit as I have seen 60's used in alcohol pro stock drag cars that would do low 10's and the Strange Axles never even worked up a sweat when stock ones were twisting)  Plus you will have a lot more wheel options with Dana's that do not exist with Rockwells. You have to look at big picture. And finally if you are hard core off road you do want to balance strength and weight. An extra 1500 lbs is no good in mud or slippery hills. When mud gets really bad and deep, all thing being equal tire and power wise, the one that is a noticably lighter will prevail 9 times out of 10 and carry the day.  If you do not believe me, throw an extra 1500lbs in your rig next time you go mudding in deep goo and leave it in there when you try to pull it out when it becomes stuck. Bigger and heavier is not always better. As far as the gas thing if you can get 6 to 8 on the street vs 2 to 4 mpg, do the math and see how much less money you will have left over for goodies and repairs because it will take a lot more engine mods to give you the same "seat of the pants" with rockwells than with Dana's.  

you have perfectly valid and good points, and i understand what you're saying about the weight.  that extra weight will sink you faster, but would you rather have to winch out, or replace an axle in 4 feet of mud?as for the gas mileage, i don't know how fair it is to cut in half your mileage with the rockwells.  maybe that is the case, but that seems like a sharp drop.  don't forget, you're gonna need a lot of gear in it anyhow being that the IROKs are a solid 50" in diameter...

either way, let us know how things turn out.

1.  Cost-- Have you priced D60's lately?  Have you priced aftermarket parts for a D60 lately?  A pair of D60's outfitted to handle 49's is right up there in Rockwell territory.  And it's still not as strong.

2.  We're not talking about race cars; we're talking about heavy, offroad trucks.  Drag cars don't run granny lows, low range t-cases, auxillary low range boxes, and 6+ to 1 gears.  Nor do they run 49's, climb rocks, or plow through deep mud.  You can't honestly expect us to believe that an axle out of a 10 second car could survive in a built, offroad truck that sees heavy use.

3.  Sometimes added weight is the price we pay for a truck that will perform to our rocky, muddy expectations.

4.  6-8 MPG on 49's?  You're dreaming.  Even without the added weight of Rockwell's; it's not gonna happen.  It doesn't matter what axle is under your vehicle.  It takes a lot of horsepower to adequately turn 49's in mud and climbing hills.  Plus, a vehicle with 49's is more than likely not someone's daily driver.  1 or 2 MPG difference doesn't mean squat offroad.

Have you priced rockwells?  D60's are cheaper to build. THey are reasonable at a bone yard and you can upgrade axles for a few hundred bucks each axle assembly. If you are stupid enought to buy a D60 already built and marked way up by a vendor that is your fault not mine that your D60 costs so much.

Weight (and axle clerance)is your enemy in mud bogs anyway you cut it and rockwell is not a prime choice for this. BTW I used to run 5.38's in drag cars and I have seen as deep a 6.14 run in them with small blocks turning 8000rpm plus thru the traps. (when I was a "kid" a serious street rod had minmum 4.10 axle with 4.56 the favorite of hard core drivers and some ran 5.13's with small blocks on the street! 396 chevelles with 4sp and 4.10 to 4.56's were very popular and a force to be reconned with as were the 440 six paks and 421 tri power Pontiacs. You guys today do not know what real HP back then was like) A 700 to 800 HP motor "dumped" at 6500 or more RPM suddenly on a rear end with 13 inch or wider slicks is far more axle stress you will never see off road with big tires. I have seen stock axles wound up like rubber bands and ring and pinions stripped of their teeth. I saw first hand what the weak links were.

On MPG,(and it is not just MPG, it is GPH too or gallons per hour) properly geared and properly inflated tires, 6 MPG or so is doable with 49's (not at 70+ MPH though) with Dana's. With rockwells and extra gearing and you will get half that on and off the road so you will have shorter wheeling time between fuel or have to carry a lot more fuel.

My "Ideal" truck for my off road purposes would be a 1967 to 70 1/2 ton Chevy/GMC short bed 4x4 with a stock 6cyl, 5.13 gears, a very mild lift, 33's,  a stock NP205 and the only "upgrade" would be a modern 5sp manual with OD and torenson gear differntails in stock axles front and rear. It would be a nice balance of weight and functionality, reliabilty and abilty and be able to run all day on a tank of gas too. ^'s of the mid to late 60's were very strong engines for their size and had great low end torque and smoothness.  If I was mud pit racing it would be a long bed truck with D60's, some nice wide nasty 38's or 40's, a tricked up small block with a big snorkle, a automatic and 5.38 or 5.57 gears to keep engine in power band (maybe even 6.14's, I would have to see how it pulled in high range)

I will not debate you further on any subject, or respond to any of your emails.  You are a man obsessed with proving that your opinions should be shared by others.  Again personal preference is key to any decision.  I will not waste any more of my time on your surmons.