The Stovebolt Site Forums Welcome! Welcome Centre Do It Yourself (DITY) Gallery 1947 GMC EC152 - "Love at Last"

Hello All
I'm new here. I've always wanted an antique truck - I got lucky and found a beautiful 1946 GMC pickup. She's an EC152, but she's been shortened to a shortbed length. I wasn't sure what I was doing with her - I've had many other projects, but nothing this old. Over time I've fallen in love with this pickup... the beautiful purr of her 228, the starter peddle on the floor, etc.

She came with an old AM radio - a beast of a thing; the size of a toolbox with tubes! But when I got the truck, the previous owner got a Painful wiring harness and stopped after butchering the existing wiring. I've since installed an American Autowire harness, a 12v alternator, new instruments, new windshield, new brakes all around, new brake cylinder, etc.

Maybe one of you can tell me about the various tags around the pickup. Below is a pic of one in the engine bay on the driver's side. This is clearly different than the manufactures identifying tag (often called a cowl tag). There is another tag on the bed.

Enough rambling. Here are a few pics of her current state...

My 1939-54 GMC Master Parts Book says that your "1574-159069" tag is a "cab or body number" for a 100 thru 350 series AC, CC or EC truck. There is also an engine serial number stamped as shown below.

What is the purpose of the two plastic boxes mounted on the firewall above the heater hoses?

The two plastic boxes are really just one - just the shape of the cover. It's a junction for the big HOT cable.

Welcome! Nice looking truck!

I notice the title of your thread says 1947, but the text says '46. I'm assuming the '46 is correct? (My fingers slip too once in a while! )

Bill - Thank you. Good to know. I've never seen these on other trucks - thing of the past probably.

Rich, it's a slight technical thingy... She was built January of 1947 but she's 1946 all around. I hear that most people regard 47's built in the first half of the year to be 46 models.

Post the numbers on the id plate, engine id, etc and know for sure what it was originally titled as.

@Otto: Thanks. I have the original title, so I already know what it was titled as. Thanks.

Interesting. So the vehicle was a '46 design, built in '47, but sold by Chevrolet as a '46.

Otto - Here's some info with a better description of what are known as 1946 2nd Series trucks like his truck.

The "1946 2nd series GMC" refers to the GMC trucks that continued to be sold under the styling of the previous C-Series/CC-Series and CF-Series/CF-Series (for COE models) for the 1946 and 1947 model years. These models were held over into the early part of 1947, with the new Advance-Design trucks being introduced around March to May of 1947. General Motors literature always referred to these trucks as 1946 model year trucks.

Exactly.

Trust me - I ended up with a heap of parts that I purchased over the winter for a 1947 GMC pickup (i.e., 47-49) and nearly none of the fit. So now I just order 46 parts and haven't had an issue yet. So I have come to refer to her as a 46.

Being that she is date-stamped as a January 1947, all the parts were made in 46 - so I makes that much more sense for me.

Well... it's technically a GMC (not a Chevy - but same diff, right?). Pretty much when WWII hit, all manufacturing was for the war effort (well, except farming and a few other essentials). Consumer vehicles didn't change from about 1941 till around 1946 +/- (till they got the manufacturing lines re-jigged; that and some are left-overs from military surplus).

It's a fascinating period of time. Even pennies were made in steel for a period (1943) - the copper was needed for the war effort.

Here - I thought it'd be fun to post a pic of how I got the truck. Actually there isn't much change visibly. Mostly she's dirty, missing lights, windshield cracked and delaminating.

Incidentally, I had a one lens for the front turn-signal (I think that's a turn signal below the headlight). It was cracked but I could read the part number. It cross-referenced to a Dodge truck of the same year. I managed to purchase NOS lenses for the old girl.

Nice truck. Here is mine. I bought it in 1997. If I can help with pictures please let me know. My email address is in my profile. I have been buying and selling parts since 1997 and I have quite a few on hand. I set up at the Hershey car show very October. Good luck!

Warpig - The light below the headlight in your pic was most likely a "marker light" (but maybe an add on turn signal) and looks identical to the newer AD series 1947 GMC's marker light design. The below pic from a 1947 GMC Maintenance Manual dated October 1947 shows the detail and looks identical to your fixtures. If you zoom in on your pic, I can also see where the earlier style 1941-46 "marker lights" that where designed/mounted on top of the headlight pods seemed to have been on your truck. The other pic below is from a 1945 GMC Parts Book, detailing the exploded parts view of the 1941-46 headlight assemblies. The fender mounted fixture could be an add on, or maybe another mid year switch over thing as they were gearing up for the new 1947 AD series truck style???

Thanks Greenie. That would be a great help. Do you have a pic of your steering wheel? Is it original? Mine is a Chevy steering wheel - cool, but wrong. Also, the original knobs have cool lettering compared to after-market; any pics of those?

Hard to say. I see other people have the headlight mounted market lights. I also see that later model 1947's have the fender marker light. I can say, mine seem original - but hard to say.

My truck is an EC - whereas your manual says CC. I wonder if that is the difference.

It seems turn signals didn't exist (well... your hand existed, but you know what I'm saying). Mine does have an after-market turn signal assembly on the steering column. But the previous owner hacked it up something terrible.

Thanks for the info.

Rick - You can see a couple more existing pics of Greenie's truck HERE, as well as lots of other 1941-46 GMC and Chevy trucks (and as listed on this page as "1947.1 (First Series) Trucks -- The Last of the "Art Deco" Series Trucks") in this 1941-46 Stovebolt Gallery Page. *

If you dive into those galleries a little deeper, some of the Bolters have included personal web pages to provide more details on their trucks. A prime example with tons of great detailed pics is fellow Bolter "JimF4160" showing off his 1941 GMC CC-101 Pickup.

I think you will find a great deal of resource pictures and info in these galleries to keep you busy, and maybe drooling - hahaha, for days to come.

* Note: I previously mentioned that your truck is considered a 1946.2 (2nd Series) truck. In getting reacquainted with this older Gallery Page, I think your truck may be better described as a 1947.1 (1st Series). A mix up in terminology and a technicality that really has no effect on the registration year of your truck. My apologies for that.

Rick - This Old GMC Trucks Pickup Serial Number decoding web page helps break down your "EC" code. It shows 1941-46 GMC Pickups used "CC" and 1946 also identified with "EC".

The Old GMC Trucks web site hasn't been added to/updated in quite some time, but still has a ton of great info that might also help with your project too.

Another example of a later 46 EC152.

16-Jun-2025 : new fuel pump. The old one was leaking. I purchased the one with the glass (I grew up with these and I like to see the gas - easy to check if you have fuel). It was $20 more than without the glass - money well spent. The rebuild kit for the fuel pump was almost as much as the fuel pump itself.

Next on my list: replace the fuel sensor.

It may be that I have the wires reversed on the instrument panel (since the wiring and instrument panel are upgraded). But I figure a new sending unit ($21) can't hurt. My first step in diagnosing would have been to connect a DMM across the old sending unit - but to properly measure I'd have to remove it anyway. Given how the gaskets on this old girl are... crispy... it seemed wise just to get a new unit.

Oh, it also could be that I don't have enough fuel to register. I've hesitated to fill her up - I'm still chasing leaks and such. I guess at this point I could do that.

That might be interesting. I went to that site - ended up in some circular links without finding the info.

Let me ask - what sort of info would I get from this decoding? My tag simply has "EC152", a serial number, hp rating (85.5 @ 3k!!!), and gross weight. It seems like there would be little to decode. I guess I could attempt to dig more (the site seems a little rough around the edges - LOL). Or maybe they are referring to another tag with some other numbers?

According to this page there was only one year for EC-152, 1946.

My 1939-1947 100-970 MPB list both E and F series as 47. Later books show the E series as a 46. The E series came out after October of 46. October 1, 1946 was the model year brake-off point. All trucks built after 10/01/46 are 1947 models. (A, C and E series)

In July of 1947 the "New Design" F series trucks came out.

My paper 1939-54 100-470 models lists EC-152 as 1946 only, with serial numbers 001 thru 3121. This is probably the exact same page of the same manual I pointed to 2 posts above because the page number and "Revised August 1954" at the bottom of the page are the same. FC is listed as 1947-50.

My .PDF copy 1939-53 100-370 models also lists EC-152 as 1946 only, with serial numbers 001 thru 3121. Revised December 1953. FC is listed 1947-50.

My .PDF copy GM Parts Sales United Motors System Master Parts Catalog for GMC Trucks model series 100 Thru 470 also lists EC-152 as 1946 only, with serial numbers 001 thru 3121. Revised 2-1-56. FC is listed 1947-50.

Summary: All 3 of these documents list EC-152 as 1946 models and FC as 1947-59 models.

I won't enter the debate about whether EC-152's are only 1946 or if they continued into early 1947. What I can say is my tag and title say EC152, and my title and original title indicate 1947. It's hard for me debate the items I see in front of me. I have to side with Jim.

But what is the point of the debate anyway? I mean, is Bill attempting to indicate my truck is a forgery?

Oh... so the new fuel pump... isn't quite working well yet. With the old fuel pump my truck started easily everytime... but with the new pump it's a bear to get running. It looks to have good fuel pressure... but I have nothing to measure it by. Despite that, I wonder if this new fuel pump is crap. I can see the fuel in the glass bowl - but I can't verify the fuel to the carb... yet. I figure this weekend I'll open the carb and check the floats. Keep in mind that the carb was rebuilt a couple months ago and worked fine with the old fuel pump.

Rick - Here's a Tech Tip on testing your fuel pump written by Jerry (Hotrod Lincoln) that may help you out.

Before monkeying with the carburetor, just disconnect the line at the carb inlet and crank the engine to see if fuel is reaching the carburetor.

If it is, perform the necessary tests on the fuel pump.

If fuel isn't reaching the carburetor, you have joined the ranks of many others here, including me, who have purchased new fuel pumps that don't pump a drop straight out of the box.

No, just telling you what 3 books say.

If I only had a pressure gauge. Plus, she currently won't start - so that's out too.

As they say in the Netherlands... wat een spelbreker (what a bummer).

Thanks for all the tech-tips. I agree - I'll discon the carb; see if she flows when she cranks. If she flows, I'll attempt to ascertain the amount of flow vs crank time... Otherwise I'll see if the floats may need adjustment.

A typical fuel pump (for carbureted) is only about 4-6 psi... not a lot. If I get flow, then it's likely the carb. But I also have to keep in mind that there may be simple residual pressure in the lines.


Thanks Otto - nice to know this isn't unheard of. I admit it's been a long time since I've had to replace a fuel pump.

Your pump should only be putting out 2 psi - 4 psi. Any more than that will overpower the float valve and flood your carburetor.

My pump operates at 2.5psi.

I forgot to ask if you have an inline filter installed between the pump and carburetor? If so, it could be clogged.

The average human is only capable of producing about 2 psi if he blows as hard as he can. If you can't blow through your fuel filter, neither can your fuel pump. If it's even moderately difficult for you to blow through the filter, a properly functioning 1947 fuel pump will also have trouble.

You can buy a pressure gauge/vacuum gauge (it does both) for about $20 at any auto parts store.

Good to know. I actually don't have a gauge, but I know for most carbureted cars it's 4 to 6.

Yep - and I am considering that.

Again... good suggestion.

I think I got her going. I adjusted the floats (a few times) and examined a few things. Honestly couldn't tell you what happened. She acted like she was flooded - I'll continue to diagnose (try again tomorrow).

So, she still has a few things out of whack. She has a new American Autowire harness, new 12v instrument cluster, etc. I can't recommend them enough - best harness I've seen; made the job easy.

The horn working would be nice - I can see a cut wire at the bottom of the steering column. The steering wheel is not original - but should work. The horn is original. So I might start digging into that.

Brake lights don't work - despite a new sensor. I can jumper across the sensor to check if the new sensor is bad. Otherwise I have to pull out the wiring diagram. It wouldn't be the first time I made a bad assumption on the nomenclature of a diagram.

No signals - but I'll use my hand. Us older gentlemen are used to using our hands. I don't think the truck originally had directional signals - my truck has an aftermarket item attached to the steering column... but some maniac cut the wires into stubs.

But... I think I'll replace the inner door release handles. The driver's side is worn down a lot. This old girl has seen some miles I imagine.

Realize that the original horn electrical system did not use a relay and that your new harness probably expects to use one.

The original circuit had battery voltage going to one terminal on the horn. The other terminal had a wire that came back into the cabin and up through the steering column to the upper steering column bearing, which also provides a surface for the contact in the steering wheel to touch. The top end of the contact touches the underside of the horn switch in the steering wheel. When you mash the horn button the horn switch closes and completes the circuit to ground.

Check your new wiring diagram to see if it uses a relay. Making the change involves very little work.