71' 1/2 ton 4x4 to 1 ton running gear

[ROCKY79]

hey gents, im new here and had a few questions about the build im doing on my 71' K10 LB. i have had the truck for 6 years but since i joined the Marine Corps 6 years ago i havent had much time to work on it. i am curently in Afghanistan and buying parts for it. im planning a 2 week wrench fest on it while im on leave and get her up and running well enought to drive back to California from Montana.

Details: i have a mildly built 327 in it that puts out about 350 ponies, 4speed with a np 205 t-case. as of right now it has the half ton running gear underneath it. thats getting pulled in favor of a dana 60/14bolt ff that i pulled out of a 84' chev 1ton. the axles have 410s in them right now and im running 35-12.50-16 bfg mts on them with a 4 in rough country lift. i have been running these axles under my 79' gmc for awhile but the 79' has seen better days so im going to part her out. anyway.... my question is will these axles bolt up in my 71' with out having to move the spring perches? i also have a rear disk brake conversion for the 14 bolt. has anyone done this or have any advice or things i should be aware of ? ie: proportioning valve problems or master/booster problems. i was already planning on upgrading to a 3/4 ton master and booster set up. im planning on fully rebuilding the axles. seals, wheel bearings brakes ect. i have a brand new rough country lift, tires, rims, bumpers, inerior, new fenders, hood and grill (PO smashed into a telephone pole) radiator support, cab mounts etc etc. so as you can tell my dad and i are going to be very busy while i am on leave. i will try and post some pics when i get a chance. any advice or motivation you guys can hook me up with would be great. thanks. semper fi.

[special-K]

Hey buddy,welcome to the site.First of all I want to thank you for your service to the people of this country.The front will bolt up but the rear saddles will be a tad wider spaced on the 14-bolt.Gotta figure on moving those and dealing with the rearward facing shock mount vs the both forward on the '71 frame.No big deal,just something to deal with.I've heard of some re-using but I'd pick up some fresh saddles.Sure makes it cleaner/easier.

[drunkbus]

Some 14 bolts will have the spring perches at the correct width. I just did this on my Blazer and the 14 bolt I have didn't need the perches moved, I just had to deal with the shock mounts. I believe it's the 14 bolts out of crewcabs that are the correct width but can't remember for sure.

[ROCKY79]

thanks guys. ill be back in the states in a month. cant wait to start wrenchin on my own truck.( im a diesel mech) thanks for the tips. the shock mounts shouldnt be a big deal.

[Chevymaniac]

To the best of my knowledge the front is a direct bolt in and also the the rear, but only if it's from a 1 ton truck. 14 bolts were also used under 3/4 ton trucks and 1 ton vans, both of which are spaced too far apart for spring perches to be direct fit under your truck.

I'am doing the same install in my 71 K20.

[1tonblaze]

front axle is a bolt in. the rear 14 bolt came two ways a single wheel version and a dual wheel version . the single rear wheel truck you need to move the spring pads a dual rear wheel version you dont need to move them . putting the same set up in my blazer and i got a single rear wheel version so i needed to move the spring pads .