The Stovebolt Site Forums Project Journals Project Journals 1939/1940 Chevy GMC Frankenstein

Howdy folks,

Figured I'd break down and start one of these. I bought my first truck a 1940 1/2 ton Chevrolet last December (2022). It was it pretty rough shape but it has a title. The frame has been cut on to make room for a V8 presumably. It came with a 1940 216 with an automatic transmission mated to it of all things. The engine and trans had been pulled some time in the past but thankfully had been stored inside. 6

I posted that I was looking for some replacement cross members on a Facebook group for 39-40 trucks and a guy from down around Kaufman Texas responded that he had a 1939 GMC 1/2T that he would sell along with a bunch of parts that I was missing. No title though. He had a seat that had been stored inside in great shape, all interior metal that had been primed and stored inside the last 25 or so years. Hood was also stored inside and is virtually rust free. The truck itself was in really rough shape and had been sitting in a field outside Canton TX for the last 25-30 years. Thankfully the windows were rolled up. The 228 was locked up like ft knox. The frame was in great condition though. So I winched it up and headed to his house for the rest of the parts he had stored in his shop. We hauled everything back to NW Arkansas and pulled in the driveway around 1am.

Third and final truck is a 46 Chevy 1/2T that I picked up from a guy about 45 minutes south of me. Also no title. The cab is virtually rust free and I plan to use it for replacement sheet metal. It came with a 235 that was in rough shape so I hauled it and the crash box to the junkyard. It didn't have a bed.

Currently, I have stripped down the 39GMC down to the frame and have had the frame powdercoated. I did not have a good set of front springs so I purchased new leaf springs from general spring. I have a good set of rear springs that I am needing to clean up and paint black. I took my front axle over to Guthrie OK this last spring and had sid from sids dropped axles straighten and replaced the kingpin bushings. I have found the all three rear closed drive lines are trash and I have ordered a custom rear axle from Dutchman axles out of idaho along with a new third member. Should be here sometime in Oct. Whew buddy was that big money. I decided that I wanted to move away from the babbitt bearings and tracked down a nice running 261 in Wisconsin that I will be going to pick up mid October. It will be mounted to an SM420. I also picked up a Bellhousing that has been modified to hold my pedal assembly that should mount to the 261 and sm420. I also purchased a zenith 228 carb for the old 261 that should be the ticket. It is off a 270 GMC. Thanks Carbking for the lead on the zenith.

Parts needed:

- 1939-1940 Gmc lower splash pan

This is a lot of info but I had to catch everyone up to speed on my project so far.

Here is the Locked up 228. This is exactly how I found it in TX. no hood, cover etc. Its currently on a boat to China.

Edit: a year later I really regret this. Even if it was locked up, I could have used some of the parts from this. Lesson learned.

Here is the frame back from the powdercoater. I chose gray so that If I were leaking any fluids, they would be more visible against the gray vs a black.

Current shape of the 216. I know nothing about this engine other than the date code being 1940. The guy I bought it from knew even less. He purchased it from another guy a few years ago. He never even transferred the title. The title I received was issued in 1969. I believe I can use this air cleaner on top of my zenith 228 but I don't know 100%.

Daniel that is a great sounding project.
I like how you have gathered up parts from parts hither and yon,
for that old yella truck!
Sounds like it has had some engine mount modifications already , so a little more wont hurt!

Thankfully, the 39 GMC Frame was in such good shape. I guess sometime in the past though the 39 had swapped transmissions and it had a PTO shaft out the side that necessitated cutting a notch in the transmission cross support so I used the transmission crossmember from the 40 Chevy that was still in good shape.

So todays work towards driving this piece down the road revolved around two pieces. The steering knuckle arm and the steering gear mounting bracket. I ground down the rivets and punched them out. Into the powdercoat bucket they go. FYI I will tape the bearing surface before they go to the powdercoat shop. They're good guys, they know.

Last job for the day is cleaning up some parts in the parts washer. The pinion gear is out of one of the parts trucks and it'll eventually end up listed on ebay. The drag link is getting 70+ years of grease and rust scrubbed off to be rebuilt. I have a rebuild kit waiting that I purchased from Jim Carter this summer. The bellhousing in the basin is soaking as it was covered in a grease that resembles tar more than oil. Ill let it stew a few days. Ill probably sell it as well. It came with my SM420. I believe its for a 62-67 Chevy. Ill look it up later.

Back at it this morning with these 1939 front hubs/drums. The drums were frozen on the shoes from sitting half sunk for 25+ years. As you can see, they needed a little motivation to remove them. I began by using a big hammer to knock out the wheel studs. Once I got them out, I used a cold chisel to separate the hub from the drum since someone else had already beat the hub up pretty good. In the process of knocking out studs, somehow I broke my mini sledge. Someone tell my wife that I wasn't complaining about the studs for nothing, even the hammer gave up. Anyway, the head is loose on the handle so I'll make a trip to Lowes this afternoon for a new one. Cant win for losing. Hub #2 game me a little fit. I wasn't thinking when I drove the stud down with the lug nut still on and must have deformed the threads on the stud or the nut and using my impact it spun in the hub. Ended up needing to cut it off with an angle grinder. Last photo is everything that I am keeping bagged up and ready for a 5 gallon bucket coffin.

I figure that you cant have too many of these consumable spare parts. It's like land, they don't make any more.

On a positive note, the hammer head didn't fly off while motivating hub #2 so that can be my win for the day.

Is it an illusion or is the outer bearing area deformed on 1 of those hubs? If so you might be chasing your tail to reuse it.

Chuck

Good eye. It is deformed. I figured worse case scenario if I needed one in the future and one isn't available here or fleabay, I can try to reform it in my lathe.

$65 worth of new precision adjustment tools.

Next up for the day is breaking down some parts. The impact made short work of the 9/16 head bolts holding the ring on the carrier. I also ground down the peened dowel and drove it out to save this pinion from one of the parts trucks. (I removed this months ago so I don't remember offhand which one it came out of. Ring and Pinion will get in line for their evaporust baths. Currently I have a good hub soaking.

Bad news for the crusty Bellhousing. Must have scrubbed the thing too hard. I'm sure it would be fine but to the scrap pile it goes. I wasn't using this one for this project anyhow.

This morning I began cleaning up the drag link. First, I hit it with a power brush to knock off paint and surface rust. Next, I chucked it in the lathe and turned off 0.015". I did this to knock down the pitting. I finished up the day retapping the grease zerks. These are 1/8" NPT. Its back sleeping in the parts washer until I find my pipe wire brush to clean the inside threads.

Thought I would share some pictures of some parts that I recently picked up.

1. A NOS Lower Radiator Baffle for a 39-40. I was missing this part on both my 39 and 40 so its nice to get one in such good shape.

2. A Zenith 228 Carburetor from a 270 GMC. This was suggested to me over the phone by Jon (Carbking) for a 261.

Sad day for the 39 rear end. It is well worn on the saddles. Too much play without spending who knows the amount of time building them up. I spent half a day getting the saddles off the 40 rear end before the problems with it started piling on. The tubes were worn completely through on that one and the propeller shaft had worn through the bronze bushing at the trans output. Thus the new rear end coming from Dutchman Axles.

Alas, goodbye old friend. Enjoy the boat ride.

Not much in the way of work got done over the weekend. I spent a large amount of time devoted to researching the Zenith 228 Carburetor that I recently picked up. I was however able to start working on the old 216 engine last night (Sunday) that came with the 1940 Truck. My goal for the night was to divorce the transmission and bellhousing from the block so that I can get the block mounted to my engine stand.

This looks a little wonky because it was. I didn't have my engine hoist at my parents house where I have this stored so we used the front end loader of the tractor. The transmission came off super easy but as you all know, the rest is a pain. I don't have any photos of the end result because it was 1130PM.

I started by removing the starter from the bellhousing. Then, I removed the "Feet" that support the bellhousing to the frame crossmember. I then started removing bolts from the pressure plate. I could have made it easier on myself by pulling the plugs but I never make anything easy on myself. It sucked getting the flywheel to rotate. Finally got the pressure plate off. I then had 6 bolts in the flywheel to remove. I took a small flat blade screwdriver and punched the ears of the metal tabs that are bent up around the hex bolts down and was able to remove them with a standard 11/16 socket on an extension. After that, the flywheel came off mostly easy with some gentle raps from the dead blow. I put a rubber pad on the floor in case the flywheel dropped. The whole job took about 2.5hrs start to finish.

This morning, I made a trip to Lowes for some grade 8 bolts so that I can get the engine mounted to the stand. 7/16-14x4"

So I was able to get my engine mounted to my engine stand yesterday. The bolts in the back of the block are 7/16 - 14. The holes in my engine stand are ~15.5mm. I made some bushings out of some Oil-Filled Slippery UHMW Polyethylene Rod that I had left over from another project. Bushing length is 2.75". OD is 15.5mm. ID is 7/16. They fit like a glove. It took some work to get the arms in a position where all the bolts would thread in because of close the bolt holes are together on the back of the block. All in all about two hours of work between the bushings and getting the motor mounted to the stand.

I started cleaning up my Tie Rod yesterday. I power brushed it to knock off the paint and then chucked it in the lathe to knock down the burrs from pipe wrenches over the years. I didn't turn it down, I only used sand cloth and a file. This rod came from my 46 parts truck. It was in the best shape out of the 3 I had. I ran to Lowes this morning and grabbed some PVC caps for the 1" PVC scrap that I had around the shop. I will wipe the tie rod down with some acetone, let it dry, then put it in the tube and fill the tube with Evaporust to stew for a few days.

I pulled the two hubs out of their evaporust baths and wiped them down good with shop towels. They were nasty black but they wiped away to nice clean metal. I ran them through the parts washer and then wiped them down with acetone. I stuck them in an old oven set at 110 degrees for about 20 minutes. Before I cleaned them up, I cut out some circles with my glowforge laser cutter to fit nicely inside the bearing housings on each side of the hub. Each hub got 2 circles. One is 2.96" the other is 2.07". I cut it out of .050 chipboard (heavy cardboard. think picture frame backer.) I taped the bearing surfaces just incase and popped in the circles. I did this so inside the hub is bare cast steel. So far each hub has 2 coats of primer. Next week, I'll put two coats of semi gloss black on. Next thing is to draw up some gaskets for the hub/drum surface in Autocad and cut them out on the glowforge. I need to do some research to see what thickness to make them.

Hope you guys like my fancy paint shaker.

Daniel,

Let me guess, pic#3 is your handy-dandy rattle can paint shaker???

I like your masking circles. I'd find all kinds of uses for a laser cutter like you have. Gaskets, etc, etc.

Its amazing that a guy is willing to spend 30 minutes drawing files and setting up a laser cutter for something fancy that some newspaper could accomplish but turn around and spend 10 seconds duct taping a rattle can to a sawzall.

Speaking of gaskets, I just prototyped a gasket between the hub and drum face. It came out pretty decent I think.

More very nice work Daniel!

Hard to tell from the photo but these are small assorted frame pieces. I just dropped off 56 pieces in the bucket (Not everything was in the bucket at the time of the photo) and 13 larger pieces off to the powder coater. I didn't take a photo of the 13 larger pieces but they are bumper brackets, battery box, wheel dust shields and a spare tire carrier. Should see them in 2-3 weeks. Ill get everything laid out in a nice picture when I get it back.

This morning I pulled the drag link out of its Evaporust bath and scrubbed it with a new scotchbright pad and cleaned it with acetone. It was very nasty black. I made some quick and dirty v blocks with some scrap 2x4s on my mitre saw and taped the threads up with painters tape. Next, I put two coats of primer on it to sit over the weekend. Next week ill hit it with some black semi gloss along with the hubs.

I spent a few hours prototyping some new gaskets for the front drums inside and outside as well as a new gasket for the Zenith 228 throttle body. They came out really nice I think. I have these files in .dxf and .svg if anyone would like them to cut out.

Got my hubs and tie rod painted their last (2nd) coat of paint this morning. I didn't catch a picture of the finished tie rod but that's ok. It's just a painted stick.

Man what a long last two days it's been. I left out Wednesday afternoon on a 1500 mile roundtrip drive to Wisconsin to pick up a nice reconditioned 261. I swung by Jim Carter on the way home and was waiting for them to open the door this morning and filled my rental truck to the brim with extras. I'm going on vacation this week so it'll be a bit before I can get some pictures of the haul but boy howdy I am whooped from that roadtrip.

Well let's roll it back a few weeks ago when I began my search for a replacement for the tired 216. I wanted to stay period like but not fool with the splash lubrication or babbitt bearings. So the search began. A couple of weeks ago I saw a parts wanted ad for a gentleman looking for a 235. Another bolter responded that they had a 235 and a 261 available. It just so happened that the guy that had the two engines available was the guy that I bought the modified Bellhousing from for a 47-53 truck. I rang him up the next day and he sent me some pictures over. The 235 had been spoken for (this wanted ad was several days old at this point). Needless to say, a road trip to Wisconsin from NW Arkansas was in the works. I normally drive a Toyota Tundra but they're not known for fuel economy and in this day and age any miles I can keep off it is a gift. I decided to reserve a rental truck from enterprise. With the offset of gas savings, it cost me about $100 by the end of the trip. It was a couple weeks before we both had time to get together but finally, last Wednesday, Oct 11th, I left NW Arkansas with a goal to make it about 7 hours. I ended up pulling into a rest stop in N Illinois around midnight (I had to work Wednesday). I woke up at 730, found a McDonald's, and had about 3 hours left to go. It was a pretty morning other than the howling wind. I got there and we quickly got to work loading the engine. I casually mentioned that I was using a SM420 and planned to rebuild it and he said that he had a nice one about 20' away under a shelf. What the heck, throw it in too. We visited a bit and I was on my way just after lunch time. Tonight's goal was to make it as close to Kansas City as I could bear. I pulled into a rest stop a little after 930pm and went straight to sleep. I woke up around 7 and got on the road with about an hour to Jim Carters shop. I pulled in at 8am and waited for them to open. After I got done at Jim Carter, I swung across the state line to General spring and grabbed a pair of rear springs for 36-46 to replace my heavily worn rear springs. By the end of the trip I had that Chevy Colorado crammed so full I could barely see out of the windows.

I've attached a photo of the 216 in Jim Carters lobby and general springs shop.

Last night I started building my new rear end that I ordered from Dutchman axles last month.

A quick order breakdown:
1. H78g2 DMI Housing & Alloy axles, Ford 9, Roadster Round Back | GEN 2

2. H24a Install drain & deluxe filler-Pr

3. BS80 Bearing upgrade; Timken Set #20 with special loc rings & 471195 hsg seal.

4. TM10 3rd member; Strange Street Nod, Open-31 spl, 1350 yoke, 3.40 ratio

5. BK15 Brake kit; DMI Drum, Big Ford NEW Style Ends [BB-SB], 11"

6. h29b Install brkts, Spring pads, Pr. cust supplied (Labor only, 3" tubes only)

7. ML32 Powder Coat: 9 inch Ford housing & 3rd member case [Semi flat Black]

8. TM19e Bolt kit: 9" 3rd mem. & hsg. studs/bolts/nuts/washers, vent, hsg. seals


The interesting thing is that I got sent the nodular pro case. The gears are correct though. I have to call Monday and see why.

The first thing I did was spend about an hour cleaning out the weld spatter and shavings. I used a scotch bright pad on a stick. I wiped it out with cleaner and shop towels until they wiped clean. Next I put on the lubelocker gasket. Then I dropped in the third member. It took a little work to get it in gently with a dead blow but I managed to not booger any studs. I slid the axles in per the instructions in case there was any play in the studs. I got them snug but I didn't have my torque wrench with me and it was 11pm so this is where I called it a night. I need to run to the parts store for some rtv silicone and I need to come up with a seal driver slightly under 2.500".

I thought I would post a picture of the interesting filler neck for a 39/40 GMC truck. For those that don't know, a 39/40 Chevy radiator will not drop in. This truck is owned by the gentleman that I got my extra doghouse from earlier this week. Date code shows July 1940. Part number is 3112890.

P. S. If anyone has one of these laying around, I need it.

I got my flywheel in today from a fellow bolter. This one is a 839754 heavy duty clutch. If I can get a clutch kit for it, I'm going to send it to the machine shop to be resurfaced. This is the 9 bolt pressure plate so I have to locate one first. If you have a lead on one let me know. Best of my knowledge, you can't buy them new.

I put the final coat of paint on my axle flanges yesterday afternoon and just peeled the tape off. They turned out pretty nice.

After fighting my axles all weekend, I got them in. The left side axle went in fine and I was able to bolt the bearing retainer plate on to set the proper bearing preload. The right side however fought me. After putting it in and pulling it back out no less than 6 times, I gave up for the weekend and waited to call dutchman this morning when they opened shop in Idaho at 730. I probably spent 6 hours on it and I was at my wits end. I measured the bore and measured the bearing race with digital calipers to make sure it was fully seated and it was but I was still getting a gap around the retainer plate. Dutchman thought there was a chance the axle could be just a hair too long with the open diff. Kinda frustrating seeing as they manufactured the housing and axles from scratch (third member is made by strange engineering).

I chucked it in my big lathe with a live center and carefully (with lots of coolant) turned down 1/8 off the end. I swapped it to my smaller lathe that the axle shaft will fit through the headstock and faced the last little bit I couldn't get with the live center in the way. They are case hardened so I went slow and took my time.

That was the ticket I guess because it slid right in and the bearing retainer is flush with the backing plate now. All that's left is to swap the plain nuts for the lock nuts.

Attached photo is before I turned 1/8" off the end of the axle shaft showing the gap between the bearing retainer and backing plate. It was putting way too much preload on the bearing and completely locking the axle up. This is about 10ftlbs torque.

My latest 6 hr roadtrip was to pull this monster home. Found my GMC Grill. I'll need to straighten out the crank hole but it's in great shape otherwise. It even has the GMC only chin. Not sure what it weighs but the 12k winch didn't struggle too bad. I'd guess 8k. It has a 270 in it that supposedly turns over but the block has a crack that's been repaired.

It is a 1940 GMC AKCWX. Pretty rare truck.

Photo shows it after we finished loading but before we strapped down with chains and boomers.

Congrats on your find and getting it home.

Looks like quite a treasure trove of goodies on there.

There's certainly some good parts. Several I don't need and will put up here for sale eventually. Hate to see some of these rare parts get squished.