'79 K20 vs. an '84 K20, which would you choose?

[handloader90]

Been scouring the local Craigslist, Facebook Marketplace, various Facebook groups and am app called LetGo (this app is horrible btw) with no new results on K20's.

Still waiting to look at the '79 with the '85 as a second option.

I've got a TH350/ fixed yoke 205 in my possession so if the '79 does happen to have a 203 in it I'll just swap my junk into it. Few hour job.

 

[diesel4me]

When I put a NP-205 in place of a NP-203 in a '74 GMC K2500 I had,the front drive shaft was too long ,but the rear still bolted up fine..
I found a '69 K-20 a friend had parted out,just the rolling chassis left in his back yard,had the one year only 23" front shaft that was a bolt in fit..if I hadn't found that I would have had to shorten the original..

 

[tenderfoot]

I'm not a gambling man at all and I'd almost put $ on it not being a 203. But if someone put locking hubs and a shift kit in a 203? Would you keep it then?
Sorry, I meant a part time shaft kit in the 203. Would you keep it?

 

[diesel4me]

I would not have replaced the NP-203 if it didn't make scary noises when you took off fast from a dead stop--I think the chain in it was skipping over the sprockets maybe (not sure if the chain is used in hi range,most of the other GM cases only engage the chain in 4-lo)..

I tried adjusting the linkage to no avail,I figured the 454 in it was too much for it and probably wounded it before I got the truck,--it was covered in mud and had 36" tires and a very cobbed "lift kit",which I "deleted" and put it back to stock--and I had the NP-205 already,from a '72 K10 I had..so I decided to use it..

 

[tenderfoot]

Isn't the chain only used for the front drive shaft in the 203?

 

[Vombrown]

I gotta say that I am a fan of stock 203 trucks. They are the cat's behind for snow and ice and Mud. I don't like the added tire wear or the squeaky turns but I have had a few and found them to be excellent. Never towed much with one though so I have no input there. I wouldn't be scared of it for sure. I don't like the 203 part time kits with hubs. Something always goes wrong. My last dodge power wagon was set up like this and it was a continual problem I had to keep an eye on. I eventually traded everything out for stock and SURPRISE no more issues.

 

[imiceman44]

I would not have replaced the NP-203 if it didn't make scary noises when you took off fast from a dead stop--I think the chain in it was skipping over the sprockets maybe (not sure if the chain is used in hi range,most of the other GM cases only engage the chain in 4-lo)..

I tried adjusting the linkage to no avail,I figured the 454 in it was too much for it and probably wounded it before I got the truck,--it was covered in mud and had 36" tires and a very cobbed "lift kit",which I "deleted" and put it back to stock--and I had the NP-205 already,from a '72 K10 I had..so I decided to use it..

The chain in the 203 runs all the time and when it stretches enough it will skip and possibly breaks.
It happened to mine and the chain broke, bundled up in the bottom and wedged in and broke the case.
That was when I put the 205 in and never looked back.
203 that is not abused is the best for all weather conditions, and I had one in a 73
It was our go anywhere in a storm truck.

 

[tenderfoot]

I like the 203 also. I drove over the pass from Carson City to Sacramento once. Swear the walls of ice both sides of road were 30' high. Had 4.11s and never had to touch the brake even when gunning it past the truckers making the white out conditions behind them. Only bad thing about the 203 is when snow/ice hits it's impossible to go have fun in. Traction is too good.

 

[diesel4me]

Their main downfall was most people never even need a 4x4 and they didn't like the full time 4wd steering effects and poorer fuel mileage..the chains gave trouble in some,but for the most part they were pretty rugged,being cast iron,and they didn't fail all that often--most that did were due to the trucks being lifted and huge tires put on them,then the front shaft was removed and they drove it in "loc" constantly..

Also they were supposed to have motor oil,not gear oil used in them,many got 90W when serviced and that did them no good..

Personally if I had one that worked OK I'd just use it--I hate getting out to lock the hubs (or when I forget too!)--that is no problem with a NP-203,they dont have any hubs!..(one less thing to eff up and or freeze up too)..

 

[USSkoval]

The locking hubs would have to stay locked on a 203 unless a kit was installed to free the front

This is not true. With the hubs unlocked, you just move the shifter HI LOC. Also, a large percentage of 203's have been converted to part-time operation.

 

[tenderfoot]

Isn't running in HI loc bad on the tranny?

 

[handloader90]

If it had a 203 I would drive it home. Might drive it around for a little bit before it got dropped and the TH350/205 got installed.

I have both front and rear driveshafts still, all out of a LWB truck.

I'll keep everyone updated on the '79 as soon as I'm able to go look at it.

 

[max 02]

We got a 203 in one of our 77s it converted to part time and is fine... I wouldn’t worry about it!

 

[6.2Blazer]

I wouldn't worry too much about what year is on the title. The chances of a 30-40 year old Chevy truck of that era being 100% original is very slim. I mention "that era" because parts are so interchangeable over almost a 20 year period the square bodies were made. I would strictly go off what condition the truck is in and what possible parts it now has on it. This also means you can easily swap what parts you want in it. Personally I would choose the truck with the best body and frame (I hate body work) and then swap drivetrain components as needed. I grew up in a farming community back in the mid-80's and every farmer had a mid-70's to mid-80's Chevy square body truck. They started out as the daily drivers/daily farm use and many got transitioned to farm use only trucks by the late-80's, but can also say that very few had all original drivetrains in them by that time and that was 20 years ago.

Another comment about locking hubs and a NP203. I can tell you that part-time conversion on 203 equipped trucks were very, very common back in the day. I would tend to say that the majority of 203 trucks I knew about had part-time conversion kits that included locking hubs. Heck, I remember small local parts stores keeping those kits in stock. With the 203 chain in general I don't think it was any abnormal issue. Anytime you put 100k+ miles on something it tends to wear out.

I will also comment on the '03 truck. I bought an '03 2500HD new and can tell you it is a world apart from an 70's to 80's square body. Still have that truck with 140k on the odometer with only a few maintenance items needing addressed. A lot more power (6.0L/4L80E) than anything ever offered stock on older trucks and drives down the road much, much better. The only item that ever left me stranded was a front wheel bearing went out to the point it would lock up the wheel periodically and had to haul it home.

 

[tenderfoot]

Those are very good points. Especially if you plan to tow with which ever rig you decide on.

 

[79rustyk10]

I Hate the 203. With a passion. That said, they really aren't THAT bad. They are ****ing incredible in snow. I despise the driving characteristics, but if you don't want to whip shitties, and do burnouts, they're pretty okay.

 

[USSkoval]

Isn't running in HI loc bad on the tranny?

Nope, not at all. Unless it's with the front hubs locked and on pavement.

 

[tenderfoot]

Nope, not at all. Unless it's with the front hubs locked and on pavement.

That's what I meant. At high(er) speeds. I actually just had a 203 burn up a th350 from being in hiloc without the hubs locked. So...... Don't ask why it was in hiloc. It has the part-time shaft conversion. But that's another story.

 

[handloader90]

I've got a '72 K20 that I may be looking at this weekend also. Looks clean!!

I'll keep everyone updated on here.

And thanks to all youngish for the input and feedback.

 

[handloader90]

Here's more pics of the '73. Has the full floater. It does have a 203 in it, not a huge deal though.

Curious what you guys have to say about the rust in the beds wheel wells and the cab corner.

Truck looks pretty solid otherwise.

He said the p-pump squeal but I habe 2 sitting in the garage.

Said there was a noise coming from the rear end, unsure of what it was but it doesnt affect driving. I've got another 14BFF at my disposal but I'm hoping it's not a spindle.

Guys asking $3,500 which I don't think he's expecting to get.

What would you offer based on the pics?