1975 K10 back to it’s former glory- build thread

[Vicente Aceves]

Hello all. Let me preface this by saying I’m new to doing any kind of “build” and don’t have any welding skills or advanced mechanical skills. Having said that, I’ll be happy to hear any and all advice on what I’m doing with this truck.

I bought this truck a few days ago. It is a 1975 K10 shortbed. I’m told it’s a Silverado but don’t think I can confirm that because there is no SPID. The truck had been parked for about 5 years. It runs drives and stops but nothing I would call a reliable driver...yet. That’s my goal with this truck. I’d like to get it to be a solid daily driver.

The truck came with several parts that I think are Hickey Enterprises pieces. Like a Sidewinder winch, grill guard, axle trusses, skid plates, auxiliary in-bed gas tanks and racing harnesses and belts and rocker panel skid plates like I’ve seen in the Hickey Catalogue.

So, I’d like to keep the 70’s look with those accessories and for the most part just clean it up and get it mechanically sound.

It needs tires bad. So I’m looking for a set of rally’s. With probably 33s or maybe a little smaller. Not sure what it would look like. Anyway I sort of started with the “clean up” part of the build this weekend. Pictures to come

[Vicente Aceves]

More pictures showing what I’m starting with.

[Vicente Aceves]

And a couple more....it also had a bolt-in roll cage. Dash wasn’t cut up, which I thought was pretty cool.

The main reason I decided to take the roll cage, seat and carpet out was because there was a bunch of mouse crap inside.

[Vicente Aceves]

I should have apologized in advance for any sideways pictures. I don’t know how to turn them. The roll cage had 32 bolts I think. I’d like to clean it up, paint or powdercoat it. I’m open to suggestions or advice with that. Maybe some of you have had done the same?

[Vicente Aceves]

Starting the grinder with wire wheel pictures now. The driver side is solid but the passenger side had a a few holes a little smaller than a dime, and a few pin holes here and there. So that is pretty much where I’m leaving off for the week. I’m leaning toward replacing the floor on the passenger side. I’m able to cut it out but will have to pay someone to weld a new one in. Thanks for looking

[Vicente Aceves]

On a good note. The levers clean up pretty good with steel wool!

[burnin oil]

Looks pretty solid and a late 70s build. If you want it time period correct you will need some white wagon wheel rims.
Do yourself a favor and baking soda the battery tray and underneath it. While there flush the front of the fender out also. Dirt collects there and rots the fenders from the backside. Also clean the wheelwell lip above the tires. You will be amazed of how much crap gets stuck in there. Inside the cab the rear cab corners also. If the defroster vents flow sucks clean the duct. You will be amused by the amount of beer bottle caps and pencils you pull out.

With a stock suspension 31s are the biggest tires that will fit if you 4 wheel somewhat hard. I added plow springs, front overloads basically, and it would scrub with the wheel turned and full flex.

[Vicente Aceves]

Thanks for the info. I’ll keep that cleaning advice in mind when I get the motor out. There is a block under the leaf springs. Is this a basic lift? Also, did all the K10’s come with double shocks in front for 75? Or would that have been aftermarket?

[Vicente Aceves]

Had trouble loading pictures

[Richard]

Originally Posted by Vicente Aceves

Thanks for the info. I’ll keep that cleaning advice in mind when I get the motor out. There is a block under the leaf springs. Is this a basic lift? Also, did all the K10’s come with double shocks in front for 75? Or would that have been aftermarket?

Block in the rear was and is pretty standard for most lifts. Chevy did offer a quad shock option on the 4x4's but I do not think it started until the 80's. The factory upper mount for the second shock is a totally separate bracket. Here is an old thread http://67-72chevytrucks.com/vboard/s...d.php?t=648923 I cannot seem to find any clear pictures of the upper mounts.
BTW- regarding pictures. If you run windows I have found just opening your pictures with paint on your computer then saving will allow them to post correctly.

[Vicente Aceves]

Thanks for the info on the shocks. The windows info about the pictures is over my head. I’m going to ask my family if they know how to fix the pictures. They’re good with that stuff.

[1976gmc20]

Are you sure that's a 1975? Does it have a gas door or a flush cap?

I'm trying to remember when they changed the transmission indicator from the column to the dash. My 1973 had it on the column and I thought they were still that way in 1975 when I worked for the dealer and drove bunches of brand new ones. My 1980 was a four speed.

[Vicente Aceves]

Yes it’s a 75. No gas door. I told myself I wouldn’t buy anything else that I had to smog here in California. 1975 and older is currently smog exempt here. It has two other gas fills cut into both sides of the bed for the auxiliary tanks.

[Honest Bob]

Thats a cool truck with alot of really cool accessories!

[Vicente Aceves]

Thank you! Does anyone know if all 1975 4x4 trucks came with full time 4WD?

It looks like I have an NP203 transfer case with lockable hubs in the front. Do the lockable hubs mean I have part time 4WD? And is the transfer case shift knob original for 1975?

Thanks guys. -Vinnie

[Honest Bob]

Originally Posted by Vicente Aceves

Thank you! Does anyone know if all 1975 4x4 trucks came with full time 4WD?

It looks like I have an NP203 transfer case with lockable hubs in the front. Do the lockable hubs mean I have part time 4WD? And is the transfer case shift knob original for 1975?

Thanks guys. -Vinnie

It was probably a full time 4x4 with automatic hubs. The automatic hubs probably failed (very common) and some one installed the manual hubs.

There is some great information on the np203 here. https://www.offroaddesign.com/tech/o...al-information

[burnin oil]

Np203 cases where common and thats a 203 shifter lever. In the late 70s it was common to install a part time kit into the fulltime 203 case for gas milage. My dad said his blazer might have gained a tenth. Most of the kits I have seen didn't come with warn hubs but selectro. It has been a really long time since I have even around a 203 but as I recall unlocking the hubs on a unconverted case would make alot of racket and basically not move unless the shift lever was moved to a lock position.

[Vicente Aceves]

Cool. Thanks for the info guys

[1976gmc20]

Generally, automatics came with the NP203 "full time" and no lock out hubs, and manual transmissions came with NP205 "part time" and lock out hubs.

I think that started mid-year production 1973. My K20 that I ordered in Jan 73 with TH350 had the NP205 and hubs. It was quite a pain getting a new front driveshaft for it years later, as the parts catalog did not list a shaft for automatic and NP205. The one that finally fit was supposed to be for a 292 six and four speed

Sometime along the way - maybe 1980? - they went back to the NP205 for everything before switching to an aluminum TC (241 or something?). GM advertised this as a great new development that you could get a 4wd automatic with lock out hubs

My new 1980 was a four speed so it came with the NP205/hubs anyway. Unfortunately I had to sell it to pay for buying stuff to start a business.

[Vicente Aceves]

Thanks for the info. I definitely prefer standard transmissions, but I take them how they come.

I have a 70 K5 blazer with automatic trans and I believe it has an NP205. I’ve never seen the NP203 and NP205 side by side, but I remember the transfer case on the K5 looking bigger. It’s parked at a friend’s warehouse right now so I can’t compare the two at the moment.

I realize nothing lasts forever on this earth, but I really like the fact that some of these mass produced machines and pieces still work just fine after 50 years. Keep on Truckin’

[57taskforce]

Great progress your making here! One easy way to identify the 203 case is by the range box.

http://67-72chevytrucks.com/vboard/s...d.php?t=802109

This thread might help some. Looks like you’ve got a pretty solid truck there. Have you decided what your gonna do with your floors?

[Vicente Aceves]

Thanks! And yes that thread was helpful.

A friend of mine can weld and he wants to put in a new passenger side pan for me. Keeps him busy and he can make a little money, and it’ll get me going in the right direction. Win - Win .......but he’s about two weeks out so in the meantime I’ll be cleaning things up here and there and will be searching for some wheels and tires

[57taskforce]

Good call that’s the right decision in my opinion. Get rid of that cancer and don’t look back for a good long while.

[1976gmc20]

Originally Posted by Vicente Aceves

I have a 70 K5 blazer with automatic trans and I believe it has an NP205. I’ve never seen the NP203 and NP205 side by side, but I remember the transfer case on the K5 looking bigger. It’s parked at a friend’s warehouse right now so I can’t compare the two at the moment.

Yes, the NP203 didn't come out until 1974 or late year production 1973. I've never owned a NP203 but I drove a lot of them brand new or brought in for service when I worked at a Chevy dealer. I wasn't terribly impressed at the time and was glad that I had the NP205. Now I have a Selec-Trac Jeep and it is wonderful in "full time" 4wd but the old Chevy system just seemed clunky.

My mom bought a new 1971 K/10 350v8/TH350 and it had the NP205. Sometime after I sold my nearly new 1980 K/10 we got the "old" pickup from her when they bought a new 83 C/20 Suburban. So I have had I think three Chevy 4wds with the NP205.

As stated, the NP203 has a "range box" in front of the offset part of the case that drives the front axle. You can actually get a kit to marry the range box portion of an NP203 to an entire NP205 to get a three speed transfer case that has an extremely slow "low low range" that is useful for rock crawling.

[burnin oil]

Not all 4spds came with the 205. I have the adapter for a 4spd 203 combo. Nice setup for running around with black ice on the road. I have only seen that setup one other time.

I believe that the 205 was the go to for 1 tons over the 203. Most 3/4 I see had 205s but go either direction. I don't know if they ever made a t400/203 adapter but that seems to be the switch.