Funny story> I tested injection pumps. Customer brings in a Toroflow injection pump to be tested off a boat. It tests perfect and requires no work. He comes back a week later and said the pump we tested blew up his engine. It sucked water up the wet exhaust and hydrolocked the engine We told him it must have ran backwards. He replied it was our fault as the engine can't run backwards. I put the Injection pump on the stand and showed him it would indeed run in either direction. Later we found out he had two engines. One right hand rotation and one left hand. He had both starters off and had put the left hand starter on the right hand engine. Once the engine cranked it promptly sucked up water from the exhaust which was submerged in water.

Good Morning , everyone!

I worked in an automotive machine shop in Louisville, KY back in the early 1970's and Pepsi Cola had a whole fleet of GMC trucks with the Toro Flo diesel. The biggest problem with that engine was blowing head gaskets. The owner of the shop said that the problem was not enough head bolts, and they were not big enough. Several of those engines developed cracks in the engine blocks on the right front corner near the corner head bolt about 1 1/2" below the head/block surface. I repaired cracks on at least six trucks with the engines still in the frame. Back then Pepsi Cola would send us a set of Toro Flo heads every week, or two to get reconditioned. We made special brackets to hold the cylinder head so we could surface the heads on out Van Norman Rotary Broach. Those were good running engines if not abused.

I've always loved these oddball engines from American companies that most gas powered V8 guys are baffled by when they learn about them.❤

A truck from the days when America was great that first time around. Our attitudes about our country as a whole reflected in our manufactured products.

I donˋt know what is more impressive, Steves knowledge or his endless library. 😊

Pretty rare engine to run across now days!!!

I wanna hear that bad boy diesel six with duals run. What a unique sound it must have made on the road back in the day.

Well, Steve...you taught me something new again! Being a big fan of the Detroit diesel and being around heavy duty trucks my whole life, I can't believe I have never seen or even heard mention of a toro-flow diesel! I am so happy I found your channel , I have learned much!

I drove my grandfather’s 1962 GMC Pickup with a V-6 with three on the tree. It had a 6 foot bed and was kind of a stock turquoise color, or maybe it was just fading. I was amazed at the power and acceleration, and was throwing the dirt and gravel on a Kansas country road. Gramps and an Uncle were taking cattle to market and I was driving the pickup back to the farm a few miles. My cousin was trying to keep up with me in his Dad’s 1966 Chevrolet fleet side pickup with a 283 V-8. Yes, we were in our mid teens and driving like bats out of hell. Would have made epic drone footage. Maybe it exists in never never land somewhere. LOL.

1964 wow! If that old work horse could talk! Think of all the fine cus words and early morning flatulence that old interior has endured! That’s why the driver side door drops down when you open it ! It just looks so rugged! Dad had a ,1966 Chevy, with a straight six ,4 wheel drive, and 4:56 gears. He used it for pushing snow! He had a Fisher plow on it ! It was a half or 3/4 ton! One tough truck! He went out on Christmas of 1966,to push snow, he had contracts with local grocery stores, and what not. My poor Mom, was so pissed! But, he did it to make extra money for the family! It wasn’t his fault it snowed! 😂

Just looking at the leaf spring stack on this thing makes me grit my teeth anticipating the next bump or pothole in the road! Driving these things empty must have been a bone-jarring experience……..😮 Looking at the bare frame in back brings me back to the early 80’s when a friend of mine purchased a ‘67-‘72 Chevy pickup that was missing it’s bed and we decided to fabricate a wooden flatbed for it out in his parents garage. It was about a week long project, the final couple of days being the careful application of multiple layers of clear varnish the get the new wooden bed looking like a jewel! Once complete, the inaugural ride was performed by his little brother who promptly began tooling around in circles at the end of their cul-de-sac and ended with a loud “BANG” as he rolled the thing and scattered our freshly finished wooden bed in all directions at the end of the street………😂

Those older trucks all have such bad ass body styles n the wheels on them are always Rusty pieces of iron it just looks so good. I am absolutely in 💕. Great video 👍😊

Omaha had 1 of those back in the 70's, it was a reefer box truck carrying meat.

I love these old workhorses! I have a 67 GMC 4000 with the 351 Magnum V6 , 2 speed rearend and a dump bed that I use regularly here on the farm.

Like the 'Motorific" model truck he showed. Had a set myself as a kid in the late 60's ; found it again about 15years ago and started to collect the tracks / vehicles again as a hobby

Love those big rigs! Doing donuts in one is hilarious. Thanks Steve, again.

Your library of automotive literature is impressive. Great info man, have a good weekend.

Back in 69, my first summer job was at Harper Detroit Diesel in Toronto. The mechanics referred to these as Bedford Diesels. I came to Canada in very late 65 from Scotland, where my dad was a truck driver. Bedford where a slightly lighter duty truck in the UK. The Bedford had a unit construction cab, possibly influenced by what the Americans brought to the war effort. Back in the 60’s a lot of older trucks where still in active trunk service. Many where “ coach built “ cabs, wooden frame skinned with wooden panels, and varnished. They looked a lot better than you’d imagine from the description, as there where still a lot of craftsmanship in the workforce in those days. I remember being in lots of trucks that had the push out windshields for ventilation. Most still had the engine crank handle capability. Gardiner Diesels where highly desirable engines, followed by Cummins. Commers had an opposed piston 3 cylinder 2 stroke ( 6 pistons ) engine. As for Detroits back in the 60’s and a bit later trucks typical of the size Steve featured here many where repowered from gas to diesel. 53 series Detroits where popular. These two stroke engines has 53 cubic inches displacement per cylinder, “ Jimmy’s “ where 8V-71’s. These engines had 71 cu in per cylinder. The unique thing about Detroit diesels was that not only did come in a wide selection of block configurations, 2,3,4,6 cyl Inline engines, but also V6, V8, V12, and 2 V8 blocks could be bolted together and make a V 16. In non automotive applications, these engines could be coupled together and you could have 4 V12 engines driving one output shaft. This is just a general outline of the various options Detroit produced. An in-line 3’ 4’ cylinder head and exhaust manifolds for the most part fit a V6, and V8 respectively. All the bearings, fuel pumps, injectors, some oil coolers, rockers etc where interchangeable. By re positioning the gear train you could change the direction of rotation. If you did inadvertently get an engine running backwards, the oil pump obviously produce pressure. One more little bit of trivia about Detroits is when at idle they typically run on about 5-10 psi oil pressure. I knew a Detroit field service tech who had a governor cover from an old engine that came out of a navy landing craft. Where it would normally stamped Stop, Run, Fast, instead of fast it said “ Battle “. These governors would enable the engine to go wide open, as the landing craft was build for a one way trip to the beach as fast as possible.

Modern cars are terrific but classic cars are KOOL.

Time to do the Laundry Mat Crawl! Thanks for another video!

In the mid 1970's, I worked on the city buses in Gainesville, Fl. The original buses which had been purchased from Wallace Brown who owned and operated the bus system, were powered by Toro Flow General Motors v6 diesels. I rebuilt several and did all sorts of maintenance and repair on them. They were not particularly hardy or durable engines . They had many characteristic problems and were not comparable at all to the quality of the Detroit Diesels which we later had. I own one of them today which is in a school bus. It would sure be a challenge to get that old thing running!

Love learning about the vehicles that are as old as we are.

Yes, GMC was almost "independent" back in the day compared to the other divisions in a way. By 1972 or so, they started to become more homogeneous with the rest of GM. No VIN, can't win, but possibly made at the Pontiac, MI facility which was a massive complex in its day. There's always a chance that the frame mounted tank was added as an RPO option or by an upfitter at some point. There were lots of unique options back then and who knows. Of course, you could be correct and it's a mix and match of parts. That would of course happen out in the "wild" after many years of use. Whatever worked was often used. Fleet Owner magazine is still around. I have a subscription to it and it comes to my office.

I only remember seeing one of the Toro Flow engines. It was repurposed into a portable power unit for a sawmill, a concrete mixer and grain elevator for a farm. It still had the frame and front axle and the massive transmission had a big iron pulley bolted to it. I think they may still use it.

Happy morning with Steve in the junkyard ! No place like home .😊

I drove a 64 GMC 10 yard dump truck with a pusher axle in the summer of 66 between my junior and senior years of high school . The truck was gas powered and it too was a screamer as it had straight exhaust . V-6 , 5-speed , 2-speed axle and it would stay right with the other dump trucks . The rear end was quite different as the axles had splines that went in the outer hubs and I had one strip and the local GMC dealer had one in stock . I also had a center bolt break that held the spring pack together as seen in the video . We changed it out one day and it was a very hard job with the dump bed down and taking the u-bolts loose and getting the pieces of the center bolt out and the new one in was a hell of a job . Good $7.00 an hour job for a 17 year old kid and we worked from sun up to sun down , man it was one of our really hot Arkansas summers . The whole month of August was the hottest and we were hauling about 1,000 feet from where we loaded to where we were dumping and never could get out of 1-st gear and the dust was terrible . Great GMC dump truck and a great job making awesome cash money and $7.00 an hour was a lot of money in 1966 . Great video Steve .

As a apprentices in a diesel shop , we swapped gas to toroflows. Low end torque was amazing , Customers swapped engines mostly for mobile home totters.The transmission we used was a Clark double disc 5 speed, with the 2 speed rear end you could GO fast. Fun engine to work on. Yes the injector pump was crappy. This was early 70's and the gas crisis . Thanks for the show and tell.

First time ever hearing about this type of Diesel engine 😊

Looks good in the junkyard.

Detroit added a 8.2 liter "Fuel Pincher" V8, 4 strocke in the late 70's and 80''s in GM trucks. Grate video Steve.

Good morning Steve ,I use to drive a Dump truck . Of course it was a 65 GMC . The Jimmy's had a lot of torque . A lot of fun hauling dirt to the Dump . 1 load of dirt in an hour, to and from the dump to the job site. Lol.👍🇺🇸

My first job when I got out of the military back in 1974 was for an excavation contractor. He had about 4 or 5 dump trucks when I went to work for him and one of them was a GMC 10 yard dump truck that had a V6 ToroFlo in it. That was backed up with a 10 speed RoadRanger. I was told that this was a truck that someone had a bunch of old junk trucks and made one out of them. It also had an air brake reservoir that was about the size of a quart thermos bottle so not a lot of braking power. This thing was a dog! He also had 2 new GMC dump trucks that had 6V53 engines in them backed up with a 5 and a 4 speed Browning. These trucks had a lot more power.

I learn something on every one your episodes! Never heard of the Toro-Flow before watching this.

Sweet. A V6 diesel in 1964. ❤

I remember my friends dad got a brand new C60 Chevy in 1967. It was a V6 diesel. It had a 5 speed transmission and 2 speed axle.

I love these big trucks like this.

They were called terrible flows when I worked at a GMC dealer in the 70’s

I had a 1974 478M v6 gas in my boom truck. Ran excellent not much problems . Never saw a Toroflow run

If you have never been to Macungie PA for the annual antique truck show, you should. Too late for this year as I think it finishes up this weekend. Antique trucks are just as intriguing as cars are.

Wow, been around a long time but have never heard of the "Toro Flow" engine. Thanks Steve, another great presentation. Very interesting stuff!!!

Somebody should try to bring it back to life

Was born in 64 so by the time I saw one of those GMC diesels it was in an old truck in the 80s. At that time there was still a lot of the Chevy V8 powered old GMCs running around but not many with the GMC diesels or gas engines. Story I heard was the V6, V8 and especially V12 gassers drank fuel like crazy and the diesels just weren't very reliable. Saw a V6 gas out of a pickup apart once, the things were extremely heavy duty looking inside, like what you'd see in a diesel. I bet they shared a lot of parts.

In the mid 70's I worked for a guy who had been an engineer at GM and according to him had some hand in designing the Toro Flo diesel. I drove a truck among other things for him and , yup, it had a Toro Flo. It was the cabover like in the ad you showed. I remember it being loud and gutless but I suppose all diesels were back then. Good times..

I cleaned up a farm that the owners son had one of these engines in a Ford pickup . He had told me about it and it was on the farm laying buy a scrap iron pile. He said he was setting a a stop light in the late 70s and heard another one go buy that was in a pickup wrecker . He said if you ever heard one it sounded like nothing else.

Leaf springs are crazy

I didnt really know about two speed rear axles until i watched your videos.

My friend, had a 1970 dodge 1 ton heavy duty, and in the late 70’s, put this 478 v6 Toto flo in it, with adapter plate for the 727 torque flite trans, and a browning 3 speed under/direct/overdrive behind that..the truck, was a BEAST…he’s passed on,and I now have the truck…time has taken its toll, and while the truck is no good,,the drivetrain is still a great candidate for a new project..

My wonderful Dad was the owner of a smallish Mom & Sons trucking company called Blue Ribbon Trans. That was started by my Grandfather in 1938. Every truck was a straight job International gas, with refrigerated boxes, 18-22’ long. Then after age and growth spurt Dad had to upgrade the fleet, that meant to now replace 12 trucks and bodies. So he sent out bids to local truck dealers and awarded the bid to a local GMC dealer. That included one 5500, with a 305 V6 5 speed, then 8, 7500’s, with 351 V6’s with 5 speed trans and two speed GMC rears with 22’ refer boxes, plus one 6500, with a 351 TORO-FLOW diesel, with 5 speed and two speed GMC rear. with 18’ refer box, that we called Shaker! That I added dual exhaust with mufflers that going through the gears sounded amazing! Finally 2, 9500’s that had 401 V6’s with 5 speed and two speed Rockwell axles. That was the truck I got stuck with mostly as the bottom seniority driver, when my run was small load, occasionally if I had a big load, I would use one of the two biggest trucks, we had two Mack R100’s with 24’ refer boxes. We ended up going through another growth spurt, and bought 10 White 9000 tractors used. Alone with 6 refer trailer and 12 dry trailers, just as OPEC I, II. & III hit, followed by the peanut farmer de-regulating the whole trucking industry! That totally ruined it for all but the biggest. So between that and the dreaded teamsters union Dad closed up shop and sold out. An older cousin of mine owned a 1965 GMC Stepside 3/4 long bed pickup, that had a tired 305 V6 in it. So he bought Old Shaky off my Dad, then stripped the TORO FLOW that had recently been rebuilt, plus he took the 5 speed out and planted them both in his old pickup! He added a belt driven supercharger onto that TORO FLOW we ended up nicknaming ToroCharger! But even before that the old pickup ran and sounded like gangbusters! Full load of dirt bikes, plus trailer full of tools and bikes like it wasn’t even there! All while getting 18 mpg! After the supercharger it got over 24 mpg at 70 mph at 2, rpm’s in that 5 th gear, running the original 3:55 posi rear. Around town if you short shifted at no more than 1,200, it would get 18-20 mpg!

This felt like the take a drink every time steve says diesel game?!

ToroFlows were found in all kinds of places. New Idea used them in their Uni Carrier. It was a Self propelled power platform that could be a Combine, a Forage Harvester, a baler. Fox used them in their self propelled Forage Harvester as well; boats, saw mills, pumps, Log tenders, they were used in a variety of places.

We still have a old grade-all that's got a Toro flow that powers the truck portion. It's gutless as all get out.

I have a 478 Toro Flow as well as several of the gasoline V6's. There was also the 637 V8 Toro Flow in addition to the 351 and 478 versions.

That would make a cool engine for a rat rod project with the intake and exhaust on the outside

The "nip" seen at 2:07 sure took the "heart" out of that frame.

Wicked we had a 62. Gas 305 that would pull stumps. Loved GMC v6s.

Wow! This is the first I've heard ANYBODY even mention about 4 stroke Toro Flow diesel engines since learning about them in Diesel Mechanic school! Word was that it wasn't the most desirable engines to have among those in the trucking industry, because of numerous problems with them.

That's actually really cool! I had no idea these even existed! Awesome video Steve!

Wishing you a rapid recovery Mr. Mags!

Rockwell axles all have the sweet hubs that look like mags

A friend bought an old 68(?) GMC that use to be a GM V6 diesel. Prior owner repowered it 351 V6 gas. Use to be a county sander truck.... then went to local school. And then him. He still has it, but it's beat.

I worked for a GMC Medium Duty Truck dealer in the 90’s and I never ran across of these. I saw a 6500 with an air cooled Deutz but never a Toro-Flow. How about a “will it run” video?

GM didn’t learn much from converting a gas engine to diesel. Some 15 years later they did same thing with the Olds 350. The results were similar.

Thank you Steve. First diesel one I've seen

Love these old engines

It seems as though the only reason that landed in the junkyard was the production of the next, bigger, better truck, and the cost to keep that one on the road.

My employer in 1994 had a GMC 4500 with Turo flo diesel. It had a rotary Bosch pump on it like a IHC 66 or 86 series tractors. Before they converted it to a wheat harvest service truck it ha a 4 ton feed grinder mixer powered by that engine under the hood. It had a 4 speed manual transmission with 2 ptos. One one each side of the transmission. One powered the hammer mill and the other powered the hydraulics for the augers to load, unload, and position augers. Plenty of power. Biggest problem the said was trying to run 3600 rpm on those motors in the truck. High rpms would take out harmonic balancer. Avco New Idea used that diesel engine in there Uni Systems 705D tractor. Good work horse. Governed at 2800 rpm top side. I have one and it is fun to run.

The designation toro flow refers to the toroidal form cast into the piston to enhance the turbulence in the combustion chamber to improve the combustion efficiency of the engine.

Hi Steve, great video on this GMC diesel engine and truck. I believe the axle is designed that way to accommodate a tandem axle. I could be wrong, tho. On the farm, we had a 75ish GMC 9500 with a V8 Detroit engine. I'm not sure which V8 it was. I believe Steve has done a video of a similar truck. It's the model before the General and the square nosed Brigadier became the norm. The fuel pumps on diesels are called injector pumps and can be very expensive to replace or rebuild. I remember the big GMC truck because it was a retired Coca-Cola truck. The coke wave was still on it, but the company name was gone. Of course, it had a 2-tone red and white paint scheme. We lived a mile from the main rd, and while pulling a load that straight piped, Detroit could be heard coming up through the gears. Without question, those Detroits had a very unique sound, and the high revs made it really sound awesome. A runaway Diesel is one that starts to use its own oil as its fuel source. This normally happens to turbo diesel engines but can also happen to non-turbos. The turbo begins to leak oil, or the piston rings are worn, allowing oil to push past them, creating an uncontrollable fuel source. The only way to stop a runaway diesel is to shut off its air intake, or the extraneous fuel flow is eliminated or it suffers severe damage (seized bearings, broken rods, crank, etc. ). I've never experienced a runaway Diesel but I can only imagine it's not a pleasant experience. I'm sure a real diesel mechanic can chime in and correctly explain it better. This truck was used on a handful of occasions in the local Christmas parade to pull Santa's 🎅 (played by my grandfather) float/sleigh. I remember weeks before that having the chore of cleaning that truck up. Chopping away at caked on mud etc. Cases of black paint to clean up the undercarriage etc. One of my uncles drove it during the parade, and my grandmother, as Mrs Claus, would be sitting in the passenger seat waving to the crowds and slinging candy out of the window. Have a blessed day everyone 🤙🏼 Namaste 🙏🏼

These things were boat anchors when diesels or gas engines and anybody that wants to restore one for some reason the parts are super hard to get even years ago

Love the Toroflow engine!!! Million mile engine that never got recognized for what it was!!!

Sorry, Steve… Not to beat you down, because you are the incrediblest walking automotive encyclopedia, but… Yes, it is a four-stroke cycle, but it doesn’t operate on the Otto cycle. It operates on the Diesel cycle. In Diesel mechanics school, they had one of these Toro-Flows in the lab and it was torn down and reassembled hundreds of times, along with a CAT, a Mack V8, Screamin’ Jimmys, Cummins… etc. Do please keep these great junkyard crawls coming!

I have shop/rebuild manuals for the Toro-Flo engines. Be more than happy to send some scans of them if someone needs them. I hope to get my hands on one someday

I have seen at least two photos of the next gen GMC pickup with the actual Toro-Flow as stock. Quite rare.

Wish someone would do a "will it run" video on this engine.

My 1966 GMC truck had a 305 V6 in it new but that was a long time ago now it has a 327 in it

I’ve never seen a toro flow. Thanks for sharing Steve

I have a 1970 toro-flow and it also has the fuel opening for a seat tank but has diesel badge covering it. I sure the cab has not been changed.

Growing up we used to say GMC stands for give me competition👍🏻

GMC was awesome in their heyday. That same engine family begat the 305/351/401/478 V6s, the 637 V8 (gas OR diesel), and the bonkers 1960-66 702 V-12! (Essentially twin 351s with a one piece block, crank, & cam.) But a decade EARLIER, GMC made HD INLINE 6s of 302, 505, and even 707 CID!!

I've seen a few of those Toro / Torq Flow engines in My life. Every single one of them was where You found that one.. In a Junkyard. When I was in diesel Tech school 35 Years ago, We had one that was cutaway engine, showing it's inner works. Even then I commented to My instructor that the guts of it looked VERY weak for a diesel engine. He responded that I made a sound judgement, and when He was a much younger man, they dreaded seeing them come into the shop, as it was almost always for warranty work. Turd-o Flow is what they called them.

Some of the GMC's could be had with 2 v-6's in line ( basically a V 12) . Our 1965 GMC firetruck was in this configuration.

That's a real truck. @dieselbrothers should build 1 🙌

A friend of mine has one in his retired 1967 GMC transit bus. It runs very well and gets unbelievable fuel mileage.

Thanks Steve. I have never heard of the Toro Flow.

Would be a great truck fixed up some!! Thanks for sharing!

They used those in marine as well.

My dad owned a 1966 GMC 4000 COE with the Toro-Flo engine, a four-speed transmission, and believe it or not, a single speed rear. That thing was a brute, 55 mph top speed, but that was uphill or down. He also put dual exhaust on it and made the mufflers from well casings. Boy, that sound was unforgettable. I sure wish that I had that truck. I was 16 when I first started driving it to haul our equipment and round bales of hay.

So cool to see that toro-flo engine again we had a marine version in our 40ft mcFerson (novy) awesome find👍

I remember driving those when they were new. Not as much power or torque as their big brothers. They did not have wet sleeves either. The gas tank was for the Thermo King unit if it was a refrigerated box. Otherwise it was a factory delete. Thermo King did not offer smaller diesel refrigeration units until 1978.

Easiest way to tell if it was a cab swap is there is a vin # on the driver's side door jam ( top) and there is a vin on the ladder frame driver's side on top by the steering box.

My older bother still has his red Motorific GMC stake bed. I kept it for him until he got old enough to treat it right. :)

I bought some property next to me and there was a big 72 passenger GMC school bus with the seats removed sitting there. I wanted to move it down to the end of the property but still have it for storage. I looked it over and it seemed complete. Had the GMC V6 gas and Clark 5 speed. Several of the tires were flat and the gas cap was missing so i assumed the gas tank was full of water. I got a battery a gas can and some hose and set out to start it. Disconnected the fuel inlet hose rigged my jug up. Filled the carb and cranked it. To my surprise she started pretty easy. It ran ok but smoked badly. Got the tires aired up. No brakes but what the hell it had the hand lever E brake that worked. It was sunk into holes on every tire but in low gear it didn't even grunt to climb out. I drove it around the place and down my driveway. Tires were badly flat spotted but what impressed me was the massive torque it produced at low engine speed. Very similar to a diesel you didn't even have to give it throttle just let out on the clutch. I have a 1966 2 ton long bed winch truck with a Chevy V8 and that old bus would drag that truck off easily. I found out the engine is a 401. I read they made them up to 478 if i remember correctly with over 600 ft pounds of torque. I bet they were slow but i bet you weren't killing it at the stop light either. I considered making it a motorhome but the cost to rebuild the engine and replace all the tires was astronomical. My wife has taken it over to store Christmas decorations and pool stuff in. I asked her if she wanted me to leave a battery in it and rig a better fuel tank up so she could drive it up to the house but she declined. So the old bus sits down there sinking into the ground again just in a new spot.

7:10 Don't forget the smallest one, the 305, and the 432. And GM intro'd the Delcotron alternator in 63 on the Corvette, moved to other vehicles in 1964. So that alternator could be correct.

Steve, another excellent video. Thank you so much for bringing this engine to light. I've known about these engines for a long time. I've never seen one in real life but I've read about them on several occasions and they're very interesting to me. Thank you again so much! Look forward to the next episode and I agree with you. The junkyard can definitely be a very good classroom

That Detroit you showed looked like a 8V-71. V8 configuration 71cid per cylinder. Proper term for the Screamin' Demon was the 6-71 inline 6. I drove one that had a 6-71 blower, and a turbo in an Osh Kosh. It was fast.

So this diesel was derived from a converted gas engine? Long before Oldsmobile!

With respect may I say I believe that is a truck tractor as the frame isn’t long enough to fit a box that could handle much volume. Just my 2 cents from a retired truck driver of 47 years. 😉

My dad had a 65 GMC tandem dump truck back in 1965 he bought new. That engine was JUNK . He traded it on a 66 GMC 9500 with a 671 that lasted for ever.

As short as the frame rails are, I would think it was a dump bed, or a tow truck. The tank in the cab could have been used for hydraulic oil. I’m curious if there is a PTO on that truck.