I want to build a driver K10

[JJ55chevy]

I hope I can get a few ideas here, I want to build a daily driver 1/2 ton 4x4 that would be reliable, can get some halfway decent mileage and tow a car trailer once in a while. I have been mentally piecing together a truck and don't want to learn by trial and error. I have a 6 inch complete lift kit(brand new with 4 springs shocks drop arm etc that I got for $250) and a 700r4 transmission, and that is all. I want to start out by finding a donor rolling chassis and hopefully go with a new 350 from Jegs, the 700r4,I think I need some sort of a spacer and it will bolt to a 203 xfer case? what year axles will fit?71-72, 73-87 axles, are they all the same? they are a dime a dozen. I want to go with the 6" lift. I was thinking 33" tires and wondering if I should be looking for 342 gears? 308? 373? I figure I will worry about the body later since that will be the easy part. thanks for any help!!!!

[57taskforce]

I'm hoping you mean 205 case instead of 203. The 203 is fulltime 4x4 cast iron chain drive. It's advantage is a deeper low gear but is otherwise undesirable. The 205 is iron,gear drive and almost bomb proof. The 205 will bolt up to the 700r with a spacer. As for axles 73-87 axles will work for the most part. Rear shock mounts will need to be modified. 33" isn't much of a tire for 6", 33's will fit a stock truck. I'd shoot for 35's at a minimum to make it look half decent. As for gears with 35's 3:73 or 4:11 should be Half decent with the overdrive on the 700r.(I'd prefer 4:11 or even 4:56 but that's just my personal preference) keep in mind that it's not exactly great for the 700r to be less than ~1500 rpm at 60 mph.

[JJ55chevy]

205 must be the one I was thinking of, thanks. I forgot about the chain drive ones being full time only, that would have been a bad mistake. I am trying not to build it into too big of a truck where it is going to kill me at the pump, that is why I was leaning towards the 33's, I was even thinking I could leave out a leaf or two and see if that would make it a 4" lift and soften the ride a little bit...I don't plan on beating on my truck off-road. do you know if they make a spacer that will bolt up between the 700r4 and the 205 that will also replace the stock spacer/mount?

[57taskforce]

ORD and advance adapters both have means of adapting the 205 to a 700r. You'll need a turbo 350 205 complete with the adapter that bolts the case to the transmission. It's basically a 1.5 or 2" spacer that pushes the transfer case back because the stock 4x4 700r output shaft is longer than the th350. You can also buy the shortened output for the 700r4 to allow the 205 to bolt up with no spacer but it requires a complete tear down of the trans. I'd suggest maybe trying to sell the 6" lift or find someone who will trade it for a 4" or even a 2". Might get lucky. I really think 6" even with springs removed from the pack will be pretty tall for 33s. If you plan to run 33's 3:73 gears should work pretty good.

[JJ55chevy]

so far everything is making sense....205 with turbo 350 adapter as opposed to a manual trans...I have found a few parts trucks with manual trans but it is a good thing I have not jumped on anything yet...I am leaning towards the 1/2 ton axles so I can experiment on the tires...a set of six bolt tires and rims are so much cheaper than 8 bolt and if I find a combo I like I can buy brand new tires without breaking the bank...I'd like the put something together for around the $10,000 range...but that is just a rough figure baseing it on 5 grand for a chassis and 5 grand for a body

[57taskforce]

10,000 is a realistic number and should build you a decent driver. A 4spd sm465 205 can be made to work you'll just need the 350 adapter (ORD or advance adapters (can't remember which but I've seen them) sells a repop of this made from aluminum) and you need the 350 input shaft/adapter. This should make more sense of it: http://offroaddesign.com/catalog/NP205tech.htm

[72 Copper C-10]

If it was me I would find a NP241 for the transfer case, lower low range than a 203 or 205 and they are tough, and it sounds like a good match for a daily driver

[imjeff]

Mine is my DD. I have a 396, T-400, 3:73 hears, 4" lift and 33's. I've ran the same lift/tire size for many years and like the 3:73 gears. The only mod I'm planning is FI in the near future. I've had these K trucks with autos and manuals, both big and small block. They aren't ever mileage monsters, but compared to the cost of a new truck gas is cheap!

[JJ55chevy]

I'm liking all the input here...I am trying to stick with the basic parts that they had in the 72's other than the overdrive transmission because I am a cheapskate. we all know you can replace any part on these trucks for 100 bucks if you look hard enough, that is why I am shying away from buying some newer truck with 100,000 for 10 grand just to have the $3000 transmission go out on me. not to mention look how easy it is to throw one of these trucks together once you have all the parts. and if the tranny goes it's only half a day to swap it out. As I said before my main thing is to get the drivetrain together for now, for a body I am thinking of just buying a decent truck to drop on it and selling off the rolling 2 wheel drive chassis (or, knowing me, I will end up looking for another body to put on it like I need another project) I currently have a 69 GMC on a 72 c10 frame that I use all the time and we know how they ride like a dream but it is kind of iffy when I am pulling my car trailer, that is the practical side of this build, but I also want to relive my youth with a jacked up truck, my first truck in high school was a 72 Blazer.

[Roostboy102]

I want to do the same down the road. I already have it planned out 72 K10 long bed with a flatbed for hauling wood and snowmobiles. LS powered of course with the granny 4 speed and 205. After doing my C10 I'm sure a decent K10 can be done for $10k. Now the dreaming continues...

[57taskforce]

The hardest part I'm having in my build is finding a decent k frame that's not bent, broke or rusted. I'm kinda surprised that it's been almost 6 months and I'm still looking.

[68shortwide]

I like the idea. After the 68 and the cougar I wanna do a k10 longbed Crewcab. Yup I'm ambitious. 6.0 4x4 6 inch lift on 37+ tires for these STL winters. Subbed.

[Daman]

My '72 Daily driver, 350 260hp crate engine, th350, 31x10.5 tires. I'm getting 13-14 mpg.

The engine and tranny have been done and the axles are next. Not sure of the ratio but under 3.50. I'll find out this spring when I go through them



Sorry for the blurry pics but 2200 at 60 mph


2500 at 70 mph

[JJ55chevy]

here's another dumb question, is the 1/2 ton and 3/4 ton frame the same?..I have a line on a 3/4 ton frame with axles,transfer case and turbo 350 for $1000, the body is shot.

[JJ55chevy]

if daman is getting 14 mpg with a turbo 350 maybe there is hope of getting a liveable mileage out of one of these trucks with a 700r4? I have heard the only way you will get 15 MPG with one is to drive it off a cliff.

[57taskforce]

The 3/4 frame is heavier than the 1/2. I'm gonna run an Ls 5.3 in mine with either a nv4500/205 or a 4l80e/205 decent gas mileage is definitely doable if you build it right.

[JJ55chevy]

I am going to commit to buying that 3/4 ton frame...it is not my ideal set-up because it has 410 gears in it but I might trade them for something like 342's or 373's......it has a turbo 350 and 205 in it right now and from what it looks like I should be able to get an adapter somewhere to hook up that 700r4 to it....I will have to figure out how to post pictures on here and show some progress from the frozen tundra of Minnesota (we just got 6" of snow last night and I am picking it up with my 69 GMC1/2 ton 2 wheel drive)...updates to follow....

[JJ55chevy]

I went and got the '70 GMC 3/4 ton, unfortunately I did not know the year of it before I committed so it has the drum brakes in the front...I will worry about the ales later since they are easy to swap out at any time...right now I want to figure out how to get the 700r4 hooked up to the 205...right now it has a turbo 350 bolted to it so I just need to find out what adapter I need.....anyone jnoe off hand what and where I can get the spacer?.....is there anything else besides the spacer that I will need? tomorrow I am going to start stripping the body off the frame to make for a clean slate

[JJ55chevy]

I have another dumb question....what does a doubler mean?

[mrein3]

A doubler is two cases together, usually a 203 and a 205 with some aftermarket parts to put them together. The rock crawling guys do this to get a 4:1 advantage out of the t-case verses the stock 2:1. Not a daily driver thing.

[71blksuper4x4]

Originally Posted by JJ55chevy

I have another dumb question....what does a doubler mean?

Means it has a np205 and a np203 I believe to increase gear reduction.

[JJ55chevy]

lol...no wonder I didn't know what they were talking about...thanks!!!...I am thinking of calling a transmission shop on my spacer/output shaft...I do not know the history of this transmission and I want to end up with a new truck when I am done so I think getting the trans rebuilt and having them put in the shorter shaft would be the smartest move

[72MARIO]

I wouldnt get your hopes up on anything better than 10mpg. My TBI 350 suburban hardly gets 13 MPG to a Canadian gallon. My 67 C20 gets 12MPG our gallon is 4.54 liters US is 3.78

[WhiteWhale]

Im getting 10mpg with an egg under my foot in my DD burb with 4.10 gears



Ive got just over $10K in it right now not counting purchase price of the truck itself and still need to do the axles.

Replaced:
260hp 350 crate engine
performer manifold
hooker headers
all new exhaust
radiator/water pump
engine and trans mounts
alternator
carb
distributor
hoses and belts
bearings/seals in t/c adapter
brake booster/mc
hard/soft lines
calipers
pad/shoes
front and rear axle bearings
255/85/16 BFG KM2 on late 16in steel rims
Performance TH350 with cast 3qt sump
u joints in front and rear drive shafts
u joints/ball joints in the front dana 44

took me just over 3 months to get it together working on it a few days a week til the baby came now I only get 15-30 minutes a day to work on something small.

Looking to put in a new rear 14 bolt rear with detroit but find it difficult to pay the $2000 for one already done so I think I will pick up a NOS CUCV 14 bolt and change the carrier and gears myself. Finding the time to do it is the real problem.

With gas around $2.50 locally its nice but we will see how much the carbon tax will be in a next week for us lucky folks in CA.

[mud.man.rj]

What year are the 6" springs from, 73 and up are different length than 72 and back, but is possible to swap top springs from the old pack for proper length. This is for the front, not sure on the back length. Removing the 1st leaf from the top under the main leaf will drop the lift height about 1.5".
Sounds like a cool build, will be interesting to watch the progress.