Just for reference the "doghouse" is called a "core support" in case you need to reference it looking for parts or what ever. While that structure will have differing shapes and sizes across years, makes and models, the support frame that the front sheet metal and radiator attach to is universally called that to the best of my knowledge. Having said that it's not uncommon for it to be called other names as noted but if someone refers to a "core support" in future conversations you'll know what they're referring to. I have 0 experience with your truck so I've been keeping out of the technical discussion. No need to muddy the water with theories. Ole, Mike and Tony are sharp cookies so you're getting good advise.

@nicholas-gurin 

Hi Nick

Parts books I'm looking at list your transmission case number as being the 3 speed used in commercial trucks from 1941 to 1947, so that should be fine.

Maybe I'm missing something, but I don't see anything wrong with the way your engine is mounted either.

So I guess that leaves the radiator core support, as referred to by Tiny.

After some searching the internet for images, it appears the core support in 1940 was a little different than '41 to '46s in that it fits around the radiator core and actually wraps OVER TOP of the top tank, rather than sitting a bit AHEAD of the radiator tank.

But as far as I know, all of the front sheet metal is still attached to that support.

So the radiator core support is where I'd be looking for the answer to the problem.

Thanks, Ole!

With all of the input I have received on this forum and on Stovebolt.com, I feel more confident to move forward.

It would still be helpful if someone with a 1940 whose hood fit well could give me a measurement of the distance from the radiator brace rod holes in the top of the core support to the face of the firewall. If I had that measurement, I could pretty quickly prove that we have figured all this out, or that there is something still amiss. 

I am really grateful for all of the time folks have spent!

Nick 

Beware the approach of Frankentruck!

I just had a FaceTime call with Mike Rabaut and we compared some dimensions on my truck to the same spot on his...the results were not promising. 

He is suggesting that perhaps my assumption that the frame under my cab is from 1940 may not be correct!

The measurement from the point on the cowl where it is indented for the hood - to the radiator core support on his truck (about 33") shows that my cab may, in fact, be two inches too far back - Stovblt, TonyW and 35Mike all suggested might be the case...but as was shown in the photos of the cab mounts, holes were not there for the cab to be mounted to in the forward position.

Mike Rabaut thinks that, perhaps the frame is from a 1941 truck, but he and I don't know how to determine for sure what frame I have.

I, just now, had the bright idea to measure the wheelbase of the truck. It was not the most scientific measurement, but I came up with 115 1/2"...which seems to prove that I don't have the correct frame for the 1940 cab!

If it turns out that I just need to move the cab forward, I could drill some holes to do that - but then the pedals would come up in the wrong place for the 1940 cab toe pan. Would the pedal location be the only complication with the location of the body? If the body is moved forward 2" what about the sheet metal above the aft portion of the running boards? Perhaps that would need to be modified to be a couple inches longer?

The bed that is on the truck at the moment is just sitting on a few bits of 2x4s and it seems to be incorrect from the get-go as it is 45 1/2" wide. I assume that I could mount the bed wherever it works out best, relative to the wheel/fender/running board relationship...

It seems that I am getting into building a Frankentruck!

Is anyone aware of a specific thing to look for that might nail down what frame I have? If it is a 1941 1/2 ton pickup frame, what other issues can you think of that would complicate moving the cab forward and mounting it to a few newly drilled holes?

Things are more complicated than they looked when I took this project on...but I guess that is what makes life interesting!

Thanks for your thoughts!

@nicholas-gurin 

Hi Nick

I was going to suggest that that might be your problem, but really didn't want to be the bearer of bad news.  ☹️

Your 45-1/2 inch wide bed suggests 1939. The '39 pickups required wider fenders. The fenders were narrowed for 1940 to achieve the same overall width with the widened bed. An extra 1-1/2 inches of frame, between the firewall and the radiator would explain some of the things we are seeing in your pictures.

Mike

@nicholas-gurin 

Nick

We will talk later today, but in the meantime it appears from your wheelbase measurement the frame is indeed likely from a ‘41-‘46 model.  They measure 115”.  The rear, front, 2nd and 3rd cross members are the same for years, ‘37- ‘46.  At least that’s my understanding from checking the 1929-1942 and 1929-1946 Chevrolet Master Parts Catalogs.  

The frame assembly rails for ‘39 and ‘40 model 1/2 tons lead to a wheelbase measure at 113.5 inches.  The ‘37 and ‘40 trucks are 112”.

https://chevy.oldcarmanualproject.com/chevyresto/4005.htm     1940

https://chevy.oldcarmanualproject.com/chevyresto/4105.htm     1941

With assistance from folks on this forum and on Stovebolt.com as well, I now know that I have a 1940 cab on a later (longer) chassis.

Now I have to make decisions on what to do about it!

Do I move the cab forward and modify what is adversely impacted by that? Do I try to find a 1941 cab - or a 1940 frame?

Does anyone feel that the longer chassis is superior to the 1940 chassis?

Thoughts are welcome and appreciated!

Nick

Nick,

I apologize for not seeing your post earlier.  I have an original, unmolested (still with original bed wood) 1940 1/2 ton pickup.  I see now that you have determined that your truck is sitting on a later frame, but to answer your original question, I did some measuring.  The distance from the firewall to the rear face of the radiator (on both sides) measures 29 7/8”.  The distance along the sides of the V brace from the firewall to the hole/screw on the radiator housing is 34”, with 1 7/8” of thread exposed on the brace where it enters the firewall.  Probably too little too late, but there it is.

Good luck!

Jim

Thanks for the measurements, Jim!

After realizing that the 1940 Cab was sitting on a later model chassis, I was pretty distressed and wondering how complicated it was going to be to make things work.

I spent a couple of days moving the cab forward to the location where 2 holes on each side lined up with the mounting holes in the frame and fitting the sheet metal to see if proper alignment was possible. It seems that it is. The gaps around the hood look pretty good to me without any real effort to tweak them.

I had to unbolt the running boards from their supports to move them forward, but other than that, everything seems to be going together well. I will have to modify the running board mounting to allow for the 1 1/2" forward location, but otherwise I have not noticed anything that might preclude assembling the truck with the 1940 cab on the later chassis.

The bed I received with the truck apparently is from an earlier model, as it is about 45 1/2" wide on the inside. The bed is currently sitting on a few scraps of wood on the frame and I pushed it around after relocating the cab and running boards and it looks as though it will work out too. I was concerned that with the longer wheelbase, the wheel location in the rear fender openings might look incorrect, but that seems to be okay too.

I am attaching some photos of what the truck looks like after the shifting of the cab and (loose) reassembly. The filler panel between the aft part of the running board and the bed took a beating from the bed sitting on it prior to my ownership. Those will need to be tuned up, but otherwise it doesn't look much like "Franken Truck", does it?

I don't have any bumpers or brackets at this time, so I don't know how much the longer frame will impact the look once those parts are located and installed, but I did include a photo of how the frame and the rear end of the bed appear at the moment. (The front of the bed is sitting about 3/8" behind the cab at the moment. Not properly installed yet. That's one of my next research projects.)

Please, if I am overlooking something, please let me know! I am not very practiced at any of this.

Thanks!

Nick

@nicholas-gurin 

That looks much better!

And...

Many have remarked and complained that the rear wheels weren't centered in the opening in the rear fenders of cars and trucks of that period, and that they sat forward of center.

Chevrolet did in fact do that.  On purpose.

Your "problem" has gotten rid of that.

People will probably be asking you "How did you do that?"  🙂

@ole-olson 

I had seen posts somewhere where folks were criticizing the wheels not being centered in the opening on some example of these trucks, but I didn't realize that Chevrolet actually did that on purpose. 

What was their reason? 

@nicholas-gurin 

I'm not sure why they did that.

Some have suggested it was because the axle swings up and slightly back as you load a vehicle with a torque tube drive.

But that doesn't seem right to me as I don't think the axle will ever swing back far enough to actually center the wheels in the opening.

Even if it did, why design the look of the vehicle to seem right only when it's fully loaded?

I think it's more likely that it just fit the look or aesthetic that designers were after at the time.

Maybe they thought it looked speedy?  🙂