1968 C-20 LWB Fleetside Build Thread - crakarjax

[crakarjax]

I'm starting this post to keep track of my progress on the 1968 C-20 that I found on craigslist, and to provide a means by which everyone can tell me when I am doing things wrong! Positive reinforcement works also.

HISTORY:

This car was built in fremont, CA and spent it's life in Cali until 1996. At that point the original owner's son-in-law brought it to North Carolina. It has been through 3 engines and maybe multiple transmissions. It did come with a v-8 from the factory and now has a 350ci, with a TH-400 transmission. It's a longbed and the wooden bed slats are very rotten. The original owner used it with a camper and had dual saddle-tanks installed along with the cab tank for a total of a 60 gallon capacity.


PLANS:

- Swap 8-lug 3/4ton suspension to 1/2ton 5-bolt disc fronts and 12-bolt rear
- Nix the cab tank, making some cab space and keeping a decent capacity with the saddle tanks. I like the spare tire, so I won't go for a rear tank
- Prime the whole thing to stop the rust
- make and install a new bed
- drive it!
- ????

Now for some pics!

[crakarjax]

[echo72]

I see your truck has factory air installed on it. Good uck on your build.

[Shaky]

The underside looks pretty good.

I took the factory helper springs off of my C20. They make for some interesting spring rate changes when you drive around empty most of the time.

If I felt the need for more spring I'd put the airbags inside the springs. Just my $0.02.

[msgross]

I like the General Lee pushbar... moving this to the project/build section...

[crakarjax]

Originally Posted by Shaky

The underside looks pretty good.

I took the factory helper springs off of my C20. They make for some interesting spring rate changes when you drive around empty most of the time.

If I felt the need for more spring I'd put the airbags inside the springs. Just my $0.02.

What are helper springs? You can put bags inside springs? As you can see I am quite the noob right now.

[msgross]

the helper springs are the single leaf springs behind the axle.. you can see them in your pic from the rear.. They are basically overload springs for the 3/4 ton trucks...

Also, the engine might be a 350 (which wasn't an option in 68) but the intake and brackets all look original. You can look up the engine codes online to see what it is...

[crakarjax]

I picked up a '72 GMC recently, found on CL for about $500 plus $75 to tow. It's a half-ton with springs in back, which means front discs and a 12-bolt! I got it solely for this purpose but it also has some goodies that I can use, like a solid rear window, a surprisingly decent engine, and I'm sure tons of miscellanous bits.

I think where I went wrong with my 1968 Chevelle is I did not get a parts car to pull from. This project should be infinitely cheaper! I'll post pics of the donor car when I get a chance.

[Shaky]

Originally Posted by crakarjax

What are helper springs? You can put bags inside springs? As you can see I am quite the noob right now.

There's aftermarket companies that make air bags you put inside the springs. With low pressure, they keep your springs like stock. When you pump them up, your springs get stiffer.

If you're like me though, you'll find the stock 3/4 springs are plenty stiff.

[crakarjax]

Pic of the donor:

[crakarjax]

Changed the filters, rebuilt the carb(Carter AFB - needed it, the floats were not even close. luckily I had a rebuild kit laying around), changed the fluids and took it for a drive. 10 miles out, at 50mph I ran into problems and had only a screwdriver with me. If I more than feathered the gas it would seem to backfire, but it idled just fine. The issue was much worse under load. I played with the distributor but ended up limping home at 10-20mph. Seems like a timing issue but adjusting the timing doesn't alleviate the problem. I am going to swap to the HEI setup on the donor truck to see if it will solve the issue.

I pulled both ignition systems and the points system on the 68 seems pretty good, the internals are shiny like they have been recently replaced. I don't know how to tune points but I should probably learn in case a nuke hits...

I'm a bit worried that some internal component is out of whack like a jumped timing chain, busted rod, bent valve, or something worse. Well, at least I have a spare...


I looked up the casting numbers while I had the distributors off. Here's what I have so far:

68:
Block:
3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4
Heads:
333882.....74-80...350/400......76cc chambers
Trans:
'66 TH-400

72:
Block:
10054727...350...86-up...2 or 4...one piece rear seal, "Made in Canada"
According to PO, std bore '92 350 block, crank turned .010/.010
Heads:
14022601...80-86...267/305......1.72"/1.5" or 1.84"/1.5" valves, 53cc chambers
According to PO, 58cc 305 heads w/110 seat pressure springs
CAM: ISKY 292 MEGA cam
Trans:
? a clean looking TH350 with a 3000 stall B&M holeshot

After I get my ignition(hopefully) issue sorted out I plan to swap transmissions with my chevelle; it has a '67 TH-400 with a bolt hole for the new style filter, so I can run a deep pan on it. No clearance for a deep pan on the chevelle anyway, so I might as well swap it. The shallow pan that came on this truck is much nicer than the one on the chevelle, so I'd want to at least swap that anyway. This will probably have to wait until I have more time though.

Side note: simple green is pretty awesome. I used it to clean the HEI plug wires and it cut through the grease ridiculously fast. I used it undiluted but I think diluting will work best for smaller parts, as it seems to work better when it stays wet.

[culp7]

looks like a great project! can't wait to see the progress

[crakarjax]

Well, found out that I have a flat cam lobe, with the help of the board members. What to do, what to do. Thats what I am trying to figure out here !

[crakarjax]

2 months later, installed a new valvetrain, timing gears, water pump, distributor, and intake manifold, and removed the A/C compressor because it had some ridiculous mount that prevents me from pulling the passenger valve cover. Running better than it has in many miles! Time to DRIVE it!

[crakarjax]

Over 5 years later, I've been still driving this truck a few times a week. Still driving on the same old radials that it wore when I pulled it out of the woods, and other than removing old and unused wiring I hadn't done much of anything to it until a couple of weeks ago. I see that my old pics are dead, I'll try to revive them but in the meantime here's my current progress. Today I also removed the crossmember, trailing arms, springs, and axle frame supports.

[crakarjax]

Front crossmember progress