1970 K20 Z62 Full Restoration

[IronCanine]

I have been on this site for a good long while. Probably several years at least before I even became a member. In that time I have learned so much from this collective. More than that I have made great friends. There are very few days that I don’t text with someone who I first met on this site.

I have been inspired by the trucks and members on this board. I have seen the elder statesmen change over time. Some of the old guys answering questions disappeared and some of the guys asking questions began to answer them. I have watched the hobby itself change. I have seen values of trucks and parts explode. I’ve cranked out a few build threads of my own. And I’ve seen a couple of them go across the block on TV. All in all, a pretty fun time.

This is (likely) the last one of these trucks I will ever restore. With that in mind I begin this build thread with a lot of gratitude for the help I’ve been given, the kindness I’ve been shown and the friends I’ve made along the way. My first two trucks were a lot about family…this truck is more about my friends. Let’s do one more together.

[DeadheadNM]

I’m in the front row!

[1970cstblazer]

Looking forward to this.

[IronCanine]

I have had this truck stashed for a few years. I found it on Craigslist (like we used to) in Michigan. "California Truck" as they say. This pics posted are from that ad. I pulled the trigger on it because in a lot of ways it's what I would have ordered if I could go back in time. It's (1970 only) Dark Blue, a K20 with AC, and it was a Z62 which meant black molding. And I kinda wanted to do a white letter tailgate for a change. Needless to say "It was way worse in person than in the pics". I mean, it's a cliche because it's true.

[IronCanine]

Originally Posted by DeadheadNM

I’m in the front row!

Originally Posted by 1970cstblazer

Looking forward to this.

...speaking of friends. Pardon this tangent, I'll get back to the truck in a sec.

Pete is the scholar and gentleman of this board. The quality of his trucks are only surpassed by his character and kindness. His YE9 K20 was the first truck I fell in love with on this site and its restoration was the gold standard for me...which brings me to a story I'll tell on myself.

I had a dream once where I was a high school teacher in 1972. I was aware of the fact I'd been transported back in time. To my surprise I looked across the cafeteria and saw Pete. I couldn't believe it. I ran over and said, "Let's go down to the parts department at the Chevrolet place and clean em out!" Pete said, "I went yesterday."

...always a step ahead.

Pete will come up a lot in this thread...he's put me on some treasures.

[IronCanine]

I don't know what kind of life the truck lived, but it turned out to holier than a church pew. Somebody had a hole saw set and and rivet gun and went crazy on this truck. Only two of the rivets (pictured) could be argued to have improved the truck.

It was always gonna be a back burner project. (I picked this up before we even started on my brother's 69 K10). So I took it down to his place so it could run free on the farm while it waited its turn. I spent that time stockpiling the best pieces I could find. I knew it'd be my last...so I wanted to do the best job I could and put everything we'd learned into making this our best one.

[cericd]

Glad to have caught this one from the start. I'll be enjoying every step and taking notes.

[IronCanine]

Eric (OldYellow) is the real talent behind these builds. The metal work he has done on this truck is his best and that's saying something. We decided to try a different approach on this truck. In an effort to streamline our process and minimize the risk to finished pieces, the roller would be assembled at my shop and the body worked and painted at his. And then we'd marry them. (SPOILER ALERT: They aren't married yet, so you'll find out when we do how it goes)

So Eric pulled the frame, got it on the rotisserie and patched like 1000 holes, replaced so missing brackets and added one...The Z bar bracket...because as much as I wanted to build a real SPID this time, I couldn't help but make a few changes....the first of which was to convert this automatic to a 4sp.

[IronCanine]

Originally Posted by cericd

Glad to have caught this one from the start. I'll be enjoying every step and taking notes.

I love getting the band back together.

[IronCanine]

The goal of this build is to produce the closest thing to a factory result as we can. That means NOS where I can. Date code correct where I can. Factory markings were appropriate for a late 1970 Fremont truck. It won't be perfect and I'll take some license...but I'll try and point it out when I do. Let's start with axles.

HO52s are tough for parts and getting tougher. But I was able to manage.

I expected my truck to be a 4.56 (which I think was the standard gear for 70 K20s), but it was 4.10s and dated right for the build. I got lucky (one of many Pete tips) and jumped on a rebuilt locker that Mike Cofield had on the board (hence SPID change #2).

Here's a good axle thread: http://67-72chevytrucks.com/vboard/s...d.php?t=200268

I used Raybestos 2009R drums.

[IronCanine]

Here's a tip...NP205 output shaft fits the rear hub bearing perfectly. Like GM made it to press that guy in.

Mine is a 70 so it has 1/2" wheel studs...and for whatever reason I had to go with slightly longer than stock on the rear. This is documented on other HO52 specific threads. The big challenge for me was my press wasn't big enough and my wheel stud puller/bearing tool wasn't up to the challenge. I had to have my wheel studs pressed in at a tire shop. You cannot talk them into carrying about your parts as much as you do.

[IronCanine]

Here's a pic of the brake set up just to prove I did it because it's a PITA. The only parking brake gasket that I'm aware of that you can buy is from LMC. See it next to OE piece on the leaf spring. It obviously doesn't match. I got some material from McMaster-Carr and made my own.

I believe this axle got painted as a unit from the factory with the stud threads masked (not the ends). Like most things on this truck, my primary reference is JoesJunk's 1971 10k mile K20. That truck is a time capsule and just happens to be a Fremont K20 built a few months after mine. And Joe was gracious enough to let me come and photograph that truck so that we've got the best chance of getting this truck right (or as right as possible).

[68bowtie]

Subscribed

[IronCanine]

I got a 1970 Corvette Chassis detailing kit (a lot of places carry these gas tanks.com or Zip Corvette) because...surprise, surprise...they used the same colors, paints, inks, etc. And it's an easy solution.

Again, really trying to copy marks that are clearly original to the truck or if pieces were missing (foreshadowing), good original examples from my plant, Fremont. Larry (davischevy) was super helpful on this. He has another build that I love, Arkansas K10, (https://67-72chevytrucks.com/vboard/...d.php?t=755797), and it is an all original Fremont K truck that he documented well.

I don't know what many of these marks mean...just trying to copy what was there.

[IronCanine]

Originally Posted by 68bowtie

Subscribed

Awesome!

[IronCanine]

Now the front axle was a different situation. We have always done a disc brake swap on the drum/drum trucks we've done in the past. And I fully planned to do that from the jump. Very early on I picked up a donor axle and stuffed it in the corner and even went about collecting things I needed for it (namely dust shields).

But the closer I got to build time the more I began to toy with the idea of keeping the original drum Dana. Swapping the axle seemed like a step in the wrong direction for a truck we were trying to make so factory correct. But I was a little concerned about getting parts for it. That ended up being justified.

[Louisvillekytruck]

Great project Brad

[IronCanine]

Now here is one of my first and more aggravating mistakes. I like to be as efficient as possible with these builds. My goal is nine months (like a baby), but definitely less than a year (probably miss both on this one). Eric's shop is very busy, so it's a get in line situation. But when it's time...it's time to go. But this one timed out at a very busy time for me personally and professionally. (Does all of this preamble feel like an excuse...it is). Point being, some steps (especially disassembly) happen in a hurry, when they can.

Remember when I said I expected this truck to be a 4.56? Once I planned on keeping the drum front, I figured that if they looked good I'd sway the 4.10 gear and pinion set from my disc brake donor to match the 4.10 locker I'd gotten from Cofield. So when Eric and I were hurriedly breaking down the original Dana, I tossed the carrier and pinion to the side (without so much as second look) and forgot about them assuming they were something I'd never use. Unfortunately they migrated to the scrap pile.

I didn't question it until I started putting the axle back together and was fighting it. (Prepare yourself, I'm going to complain about the same things in a new thread). This truck was indeed a 4.10 from the factory (no call out on the SPID). I don't guess I understand how that worked in 70 still. By the time I did return to them, they weren't something I'd put back in this truck. What a self inflicted wound. That pinion set up was a total pain. Dana puts the shims on the wrong side of the bearing for my taste. So I burned a day on my knees trying to get this gear set like each other. And I had a factory shimmed set up from the start.

[IronCanine]

Before we finish up on this axle, let's talk about the springs. This truck came optioned with heavy duty front and rear springs. I think the front springs were gray with a wide white paint assembly mark on the front. Here you can see it on Joe's truck...and I've seen other examples too. But this is obviously a hard area to hold original paint. The gray is "Dove Gray" as recommended by Corvette folks for the rear horizontal leaf on C2s.

I ordered new springs from General Spring. Like everything else now, what you get from them has changed. The spring clamp is a crimped style. I was unable to come up with an original spring clamp, so we fabbed one. We had to cut that extra curl off the middle spring...but we did not scallop the ends as they were from factory.

The spring liner material is cut to fit and not exactly the same as OE. I'll talk more about this later, but all my hardware was replated/finished by Denver Metal Finishing.

And HOOKS! One more little tweak to the SPID. It's a problem.

[IronCanine]

Originally Posted by Louisvillekytruck

Great project Brad

It's fun so far. Thanks for jumping on!

[IronCanine]

Possibly the single most ubiquitous NOS part out there for 4WDs (besides the spring capture kit) is the rear spring shackle kit. Mine (like I'm sure most) came rusty in the box. Evaporust is a personal favorite.

Even though I picked up that safety spring retention kit, I chose not to use it. Cuz...it didn't come that way and I don't anticipate driving it in a way that breaks a bolt or spring mount. And then you couldn't see the white paint I put on there

[IronCanine]

Now back to this drum Dana. Probably the most challenging part for most would be the drum itself. This drum I used is actually listed for a Dodge (van I believe). But it fits like it was made for it. Part number 9625DGS.

But there were other bits that turned out to be slightly more challenging. First I was missing a dust shield on my long inner axle. And like a lot of pieces, this axle being more or less a one year only open knuckle drum made it unique. Believe it or not I found an NOS replacement at OldsObsolete...at least I found it on their website. It took them three months to find it in the warehouse. They weren't, shall we say super sweet about it, and I paid way too much for something nobody else would ever want. But it kept us from having to make it and the build kept matriculating along...

[IronCanine]

The other big challenge was the lockout hubs. This truck had the first gen Spicer lock out hubs. The most obvious difference is that the dials are red instead of blue and don't say Spicer. But the trim ring is different too. There is a slot for an O-ring in the second gen, that is not there in the first gen.

Now I got incredibly lucky (this theme will repeat) and was able to put together two NOS red hub dials. First gen rings I knew would probably be near impossible. So I set out to recreate (and did) the center "Spicer-less" emblem with the intent to make second gen dials look like first gen dials and use my NOS second gen trim rings (thanks for those Pete).

I did that...and they looked good. But I could see the difference between the NOS and my reproductions...and much like the drum/drum deal started to think about ways to make the NOS 1G dials work with my NOS 2G rings.

A little measuring and a few orders to McMaster-Carr again and I found a square O-ring that married them up perfectly.

Thanks again to Joe for the period Spicer assembly manual.

[IronCanine]

Even though the rings were NOS...I did send them to the chromer for freshening up. It's not the best feeling torquing those bolts on that chromed pot metal.

Front studs were listed stock length.

[IronCanine]

If there are any questions about the tire choice...just direct em to the guy in the cowboy hat.