64 GMC I1000

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Craig Nedrow

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Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
You gotta a plan! Keep us updated, and please, when you get the dual exhaust, I want to hear it!!
 

Jethro224

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Jim
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1980
Truck Model
K20
Engine Size
350
I can sure do that. Might be a little while.

There's a bunch of stuff I've already fixed since I brought her home last April. I suppose I could make this a build along if there's interest.
 

Jethro224

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Jim
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350
Got back from the parts run road trip. I'm gonna be stylin' soon as spring hits.

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The chrome came from Amazon. The rest I got today for a screamin' deal.
The headers are coated. Everything should clean up purty.
 

Craig Nedrow

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Craig
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1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
Heck yeah Jim!! what a find. Impatiently waiting!!
 

Jethro224

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Since there seems to be some interest in this old truck I guess I'll start by telling you all about how I accidentally bought it.

About this time last year I decided I should buy a car that gets better gas mileage than my 99 suburban. A V6 Mustang should do. So I started looking on Facebook marketplace.

Nothing panned out. All the good ones were gone. I didn't want a convertible. Wasn't in a hurry so I just kept searching.

For whatever reason this 64 GMC popped up on my search. I've owned a few Chevys that style. Cool truck. Keep scrolling.

It kept showing up. After several more times I had to click on the ad. After several more times of clicking the ad I had to send a message. After several messages I had to drive 300 miles to go buy it.

It was fate. I swear I tried to resist.
 

Jethro224

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Jim
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1980
Truck Model
K20
Engine Size
350
So, since it drove and stopped, against all advice, I drove her home 300 miles. Used 10 quarts of oil but I made it.

Got home in the wee hours of May 1st last year.
(Had that wrong. Edit)

The guy told me it was the original engine. It wasn't. Turned out to be a 250.

I ended up driving 3 hours the other direction to buy a 230, which is what came in the truck, after finding barely any compression in the #6 cylinder.

Other than that the fuel pump was leaking pretty bad and so was the carb. Nothing worked on the dash but the speedo either.
 
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Jethro224

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Jim
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Engine Size
350
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Before and after pics in the wrong order.

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Of course I had to put a new clutch in there since I was there...
 

Jethro224

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Jim
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1980
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K20
Engine Size
350
If you look close you'll see a big difference in the wiring between the dirty before pic and the not as dirty after pic.
The entire wiring system on the truck was a mess! I started with the engine harness and upgraded to an internal regulator alternator.
 

Jethro224

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K20
Engine Size
350
A previous owner or 2 had been under the hood "fixing" electrical stuff before. There were several wires to nowhere and a few that went where they didn't belong. Got all that straightened up. Looks a lot better and getting rid of the external regulator cleaned things up a bit.

I'm wondering if I should have fused the one hot wire from the battery tho...
Any advice?

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Jethro224

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Location
Illinois
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Jim
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1980
Truck Model
K20
Engine Size
350
When I got er fired up again the fuel pump on the 230 was leaking. Fixed that and the carb started leaking. Rebuilt the carb and it still leaked.
Bought a rebuilt carb for way too much $. It was NOT WORTH IT.
The rebuilt carb needed work to be usable. But once I got it going the truck runs decent.

All this trouble was what made me start thinking about a better manifold and carb...

Amidst all this going on I remembered that I had a whole NOS set of Monroe Magnum shocks out in the garage. So I put those on. Made a HUGE difference.
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Snoots

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Roger
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1973
Truck Model
Jimmy Sierra
Engine Size
350 w/203
When I got er fired up again the fuel pump on the 230 was leaking. Fixed that and the carb started leaking. Rebuilt the carb and it still leaked.
Bought a rebuilt carb for way too much $. It was NOT WORTH IT.
The rebuilt carb needed work to be usable. But once I got it going the truck runs decent.

All this trouble was what made me start thinking about a better manifold and carb...

Amidst all this going on I remembered that I had a whole NOS set of Monroe Magnum shocks out in the garage. So I put those on. Made a HUGE difference.
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That yellow wire in the top photo has GOT to be replaced!
BTW, Looks like it's coming along nicely!
 

Craig Nedrow

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Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
Sharpe eyes Snoots!
 

Jethro224

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Illinois
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Jim
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1980
Truck Model
K20
Engine Size
350
That yellow wire in the top photo has GOT to be replaced!
BTW, Looks like it's coming along nicely!
Thanks.
That's an optical illusion. The yellow wire is actually a brand new one. The fuzz is on another one of those resistor wires. It's got like a cloth cover on it. I don't know where to get new resistor wire and the part in the wrap looks a whole lot better so I left it alone.

You can see it better here.

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And that green wire wrapped around the radiator hose goes to the temp sender.
These are kinda old pics...
 

Jethro224

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Location
Illinois
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Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
Now that I think of it, I think that's the resistor wire that feeds power to the coil. I need to check my wiring diagram. Probably the reason my HEI wouldn't work right.
That's high on my list of stuff to do.
 

Jethro224

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Posts
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Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
At this point it was the beginning of September. I had been driving the truck some. In the daytime. Not too far. Remember, no dash but the speedo.

I had bought a box of stuff from LMC and was fixing little things. Door lock was one.
The ignition switch was wonky and I thought I'd fix that one day real quick. Just replace the Ace Hardware one for a stock style. Easy peasy. Nope.

When I pulled the switch out of the dash most of the wires just fell off. I had no idea where they went. Finding the right diagram was a challenge until a guy on the 64-66 GMC club forum hooked me up.
By then I had traced back pretty far up the harness and found a whole slew of issues. Ended up pretty much rewiring the whole cab. Tried to keep it as stock as possible. Used parts of 3 harnesses.

Before.
 

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