Picked up a 73 C20, low original milea
 

Well hello all!

I haven’t been on here much lately because I really haven’t been tinkering with my trucks lately….But! This weekend I picked up a 73 C20 with only 31k original miles! She lived on a farm in the middle of Illinois her whole life. I hopped in and drove it 240 miles home without a single issue. It has a 350/SM465. Not sure gears yet. I think 3:73.

Here are some pics after a quick wash and before I really started cleaning!

Re: Picked up a 73 C20, low original milea
 

And here are some after I pulled everything out of interior and cleaned up 50 years of dirt. I brushed up loose rust and put corroseal on to stop it from spreading. I also scrubbed all the upholstery and the floor mat.

Re: Picked up a 73 C20, low original milea
 

Then I thought I would do a little buffing and get the front bumper looking a little better.

The plans are just to drive it and leave as original as possible. It isn’t perfect, so I can still use it as a truck and not feel bad about it.

Re: Picked up a 73 C20, low original milea
 

Looks great! Enjoy!!

Greg

Re: Picked up a 73 C20, low original milea
 

Nice find and the bumper turned out great! I like that green as well, Congratulations on saving another one Cort!

Re: Picked up a 73 C20, low original milea
 

Noice!

If you find the SPID label I can probably tell you what rear axle ratio it has.

K

3.73 is standard; 4.10 and 4.56 optional:

https://www.gm.com/content/dam/compa...olet-Truck.pdf

Re: Picked up a 73 C20, low original milea
 

outstanding!

Re: Picked up a 73 C20, low original milea
 

Here you go! It doesn’t list the RPO for the axle. As you can see, she is a bare bones unit. The only options they chose was gauges and power brakes. It is a radio delete, lighter delete, everything delete truck. Haha.

Re: Picked up a 73 C20, low original milea
 

Here are some pics of the engine compartment. Only things changed so far is radiator and HEI. I need to get some valve cover gaskets on her before I drive too much more.

Re: Picked up a 73 C20, low original milea
 

Wow. Such a killer truck.

Re: Picked up a 73 C20, low original milea
 

Wow! Thats nice. I would have sworn that was a Pearl Gray interior, but the spid says Slate Green.

Re: Picked up a 73 C20, low original milea
 

nice score, congrats.:metal:

Re: Picked up a 73 C20, low original milea
 

That MFG date of May 97 on the valve cover is interesting. Whatever the story is on the motor, nice looking truck.

Re: Picked up a 73 C20, low original milea
 

It actually says May 1973, you just can’t really tell in the picture. And thanks!

Re: Picked up a 73 C20, low original milea
 

That’s a great truck. Every now and again a nice farm 3/4 ton turns up. You got lucky.

What rear axle does it have? Semi or full float? If you’ve got a full float 3.73 that’s pretty nice with the 465.

I’ve got the same engine/trans combo is you (just coming up on 50,000 miles this summer) but with a 4.10 in the back. It turns a lot of rpm on the highway.

Re: Picked up a 73 C20, low original milea
 

Thanks! The rear is full floating. I just don’t know what gears yet. I drove it home at 60-65 mph and felt that was as far as I was comfortable winding her up without a tach.

Re: Picked up a 73 C20, low original milea
 

That makes more sense. It really looks original. I bought a replacement motor for my 75 around 97 and it was one of the black Hecho in Mexico 350s.

If that is the OEM exhaust system, make sure it isn't one of the double wall exhaust pipe setups on the y-pipe. If the inner wall collapses, all sorts of bad things happen.

Re: Picked up a 73 C20, low original milea
 

Good to know! I’ll watch out for that. They pipe I’m pretty sure is original.

Re: Picked up a 73 C20, low original milea
 

Always liked that color and ‘73’s are just cool. Nice truck!

Re: Picked up a 73 C20, low original milea
 

Mine still has the original Y pipe. What’s going to happen to it?

Re: Picked up a 73 C20, low original milea
 

Mine had the build sheet under the passenger side of the seat - tucked in the springs. My rear axle code is GT5, which is a full float 4.10

Re: Picked up a 73 C20, low original milea
 

IF it has a double wall pipe, the inner wall can collapse and block off the exhaust flow. Symptoms are crappy performance and carbs that keep going bad. My dad bought what is now my 75 in 78. Its performance sucked. It had problems going faster then about 60(during the 55 speed limit era). Plus the carb kept going bad and flooding out. The thing looked like a diesel going down the road. When the thermostat stuck shut, the head gasket cracked. Turned out to be a good thing. While the heads were off, I looked down the exhaust pipes and noticed that both were blocked off even though the outside looked normal. Took it to an exhaust shop and they said they had seen several of the newer GM trucks with that problem. Swapped to a dual exhaust and suddenly it ran much better. 90+ with more left(younger and stupider).

Don't know if the double wall Y-pipe was a converter thing to keep the exhaust hotter or a noise thing. Mine never had cats being a HD version but I can see GM using the same Y-pipe on both versions.

Re: Picked up a 73 C20, low original milea
 

Thanks!

Re: Picked up a 73 C20, low original milea
 

Yep - if it's not on the SPID then it came with the base axle = 3.73.

No tellin' what's in there now.

K

Re: Picked up a 73 C20, low original milea
 

Thanks Keith! So far as I’ve found, she’s basically 100% original. Still has the shocks on it that has the spirals in the metal. So I’m thinking still has the 3:73 as well.

Re: Picked up a 73 C20, low original milea
 

Very Kool truck! Nice find!!

Re: Picked up a 73 C20, low original milea
 

Wow that's an amazing truck. I love the originality. I'd track down a set of original hubcaps.

Re: Picked up a 73 C20, low original milea
 

I have them actually! Somebody painted them green with house paint, so I have to blast them and get them painted up. But they’re in really good shape; virtually dent free.

Re: Picked up a 73 C20, low original milea
 

She’s a beaut’

Re: Picked up a 73 C20, low original milea
 

Thanks!

Just replaced the original shocks today and went for a ride. Much better ride!

Re: Picked up a 73 C20, low original milea
 

Making her work this past weekend!

Re: Picked up a 73 C20, low original milea
 

Beautiful truck. Consider joining my FB group: All Original Squarebodies.

Re: Picked up a 73 C20, low original milea
 

Man I must say, I love driving this truck. Even with manual steering and 3/4 suspension. She’s a wonderful rig. And does awesome towing the boat.

Finally got around to getting the dash out and cleaning up/replacing burnt bulbs in the cluster. It cleaned up nice! I’m sure I’m the first person that’s had that apart since the factory installed it. Everything is 100% untouched behind there.

Re: Picked up a 73 C20, low original milea
 

This past weekend I decided to pull the engine and trans and reseal everything. Pretty cool knowing the history of the truck and that I am the first person to pull any of this apart since it was assembled at the factory.

While I was at it, I figured I would put in an RV cam. Next year I want to get a slide in camper and tow around the boat to different lakes, so figured it wouldn’t hurt to wake the engine up a bit. Here are some progress photos:

Re: Picked up a 73 C20, low original milea
 

I was tickled at how rust free everything was. All the bolts came out without breaking a single one!

Re: Picked up a 73 C20, low original milea
 

Got the engine apart, new cam, lifters, and double roller timing chain. Then all new gaskets, rear main seal, and some paint! Here are before and afters:

Re: Picked up a 73 C20, low original milea
 

Couple more. Rebuilt the carb and broke-in the camshaft in the other night without a hitch. Been driving last couple days; it runs so good! I’m excited to get this thing loaded up and make some trips!

Re: Picked up a 73 C20, low original milea
 

Sweet!

Re: Picked up a 73 C20, low original milea
 

Re: Picked up a 73 C20, low original milea
 

Hi all,

Been a bit since I posted. I've been restoring a 1966 Alaskan camper to put in the back of the '73, so not much going on with the truck itself right now. I did add a 100 amp alternator and ACR so I can charge the camper battery going down the road.

And added power steering and sway bar! So much better....