Muscle cars were all the rage in the late sixties and early seventies. Truck owner-operators wanted in on the action too, given the low price of fuel and the ability to roll along at 80+ mph on the interstates of the times, never mind passing all the other trucks on every grade.
Freightliner was the only company to create a new truck to meet what was expected to be a growing market with the Powerliner. It came standard with a 400 hp Detroit Diesel V12 (12V71), the CAT 3408 V8 was optional, and the top power option was the 600 hp Cummins KTA-600 with 1150 cubic inches (19 L), a lareg and heavy engine originally not intended for highway trucks. It was the biggest displacement diesel engine ever offered in regular production highway trucks. No wonder the Powerliner had a massive 2000 square inch radiator as well as numerous other changes.
The timing of the Powerliner with its 3 – 4.5 mpg fuel consumption couldn’t have been worse. The 1973-1974 energy crisis resulting in higher fuel cost and the 55 mph speed limit put a serious crimp into its sales, and it was discontinued after a few years. But during its reign, it was truly the King of the Road.
As a frame of reference, the Powerliner (center) was not just a Freightliner COE (right) with a bigger radiator. It had a unique frame whose rails widened at the front to make room for the massive engines. The windshield was larger too, as well as numerous other changes.
In case you’re wondering about the “White” part of its badge, Freightliner for years had a sales and marketing agreement with White that ended in 1975, so the early Powerliners were technically White-Freightliner; the later ones just Freightliner.
As this brochure makes clear, the Powerliner was specifically targeted to owner-operators (“O&O”) and not to fleet operators, who would not have indulged in what were the equivalent of Hemi Chargers for their fleets. The sixties and seventies were the glory years of O&Os, whose share of the trucking market was much higher back then.
Here’s the cab tilted, showing off the standard DD 12V71.
A closer look at that giant radiator and the 12V71.
Although they reflected the best of the times, the interior amenities were anything but luxurious and comfortable. The engine dog house was mammoth, for obvious reasons. I rode in some of these COEs (not Powerliners) in my hitchhiking days, and the noise was absolutely deafening. These were DD 8V71 equipped trucks; the V12 would only have been noisier yet. I did ride in one that had a big CAT six, and it was noticeably quieter, in relative terms.
The Cummins K-series engine, which is still being built today for mining trucks and such, is simply bigger all-round than engines designed for highway trucks. Its bore and stroke were both 6.25″, and it weighed about 4,000 lbs. It came in several versions: KT (Turbocharged) with 450 and 525 hp; KTA (Turbocharged and Aftercooled) with 600 hp back then, and 700 hp later in its life. There was also a KTTA, with twi-turbos, making some 725 or more, but it was not installed in highway trucks.
According to one source, the only transmissions that were fully warrantied behind the KTA-600 were the 8 and 13 speed Eaton-Fullers, but that may not be accurate.
Speaking of torque, the KTA-600 was rated at 1650 lb.ft., which was top dog at the time, along with its hp rating. But that’s just a jumping off point.
The KTA-600 was also available in select Peterbilt, Kenworth and International trucks. Here’s a charming story from an old 10-4 magazine in 2002, about Mutt Tayman’s KTA-600 Peterbilt that pulled 1007 hp at the rear wheels, thanks to a few tweaks, including twin turbos. And yes, this was his only daily work truck. (Full article here)
At age 15 Mutt started driving a truck – a 1950 Ford F8 that hauled soybeans and corn to Baltimore. In 1958 Mutt purchased a new Ford F8 dump truck, which he used until 1963 when he purchased a 1963 Autocar. Mr. Tayman never liked small engines so he purchased another Autocar in 1967 with an NTC 335 Cummins engine and Fuller 13-speed transmission. Talk about being the “king” – 335 horsepower in 1967!
Now Mutt was on a roll. In 1970 he bought a new Peterbilt with a V-12 Detroit Diesel. Keep in mind that this was a tandem dump truck with 12 cylinders and only three axles. The Peterbilt apparently satisfied his desire for power because he ran this truck for 9 years. In 1979 he ordered a new Peterbilt tractor with a KTA 600 Cummins engine and a 12-5-15-speed transmission. He waited eleven months to get this truck and then picked it up at the Peterbilt factory himself. He apparently didn’t want anyone else to drive his beloved “K” before he got to.
Mutt is still driving this 1979 Pete today. The engine has never been out of the chassis. During the last rebuild, a set of twin turbos and hydraulic variable timing was installed, along with a huge set of injectors and a high volume fuel pump built by Pat Sharp of Diesel Injection of Pittsburgh. This old faded blue Pete produces serious horsepower – 1007 to the ground!
The morning of May 18th, the date of Alban Engine’s Power Day, was cool and rainy. It didn’t take long for the parking lot to fill with beautiful trucks. But the Mutt was cool. He pulled his old Peterbilt through the parking lot and to the side of the building, almost out of sight from the spectators. We had no idea what was under the hood until curiosity got the best of us. Jerry Ray Hairhogger slid under the truck and was shocked to see a twin turbo “K”. Not only was Mutt the oldest owner-operator in attendance, but every other truck outshined his. Mutt’s Pete was a true “sleeper” indeed. This man is so cool he never said a word or showed any emotions – even when his truck was backed onto the Dyno.
After the old Pete was chained and strapped, the shifter was placed in gear and the clutch came out. The dyno rollers started to turn as the spectators watched the horsepower begin to climb. More fuel, more horsepower, more fuel again. The engine roared as the truck shook like a wild animal. As the roar got louder the horsepower continued to climb. When the power hit 1,000 HP the crowd went wild. The top horsepower was 1007 to the rear wheels. That’s somewhere between 1185 and 1258 flywheel horsepower, and well over 3,000 pounds feet of torque through a 1200 pounds feet of torque transmission. This transmission was rebuilt only once in 23 years of driving. You see, when properly driven, high horsepower does not harm the drivetrain.
The KTA-600 became legendary for its ability to make massive power, and ones used in truck pull competitions make up to 3,000 hp, along with prodigious amounts of smoke.
This guy stuffed a KTA into a Dodge Big Horn, and is pretty much unbeatable in that field. These modified engines are run at or close to 4000 rpm, twice their normal peak power speed. The block, crank, rods and pistons are stock.
If that’s a bit too smoky for you, here’s much more laid back and rather sweet video of the shooter’s dad’s original KTA-powered Kenworth. It gives a better idea of how these husky rigs sounded at work in the real world. Basso Profundo.
There’s still a few of these Powerliners out there, increasingly restored and shown at truck shows. If they have KTA power, their value goes up significantly, as not many were originally built that way. That goes even more so for the Peterbilt and Kenworth conventionals.
The KTA’s power was of course eventually surpassed by newer and smaller engines, although 600 hp is still on the high side for a regular highway truck.
But in its day, it was unbeatable, especially so on the grades in the mountains, where it could walk away from any other truck at the time.
The only exception might have been if this 1951 Kenworth with a 600 hp 2181 cubic inch V12 Hall-Scott gas engine. But it didn’t survive long enough to see the coming of 600 hp diesel trucks. What a race that would have been, though.
Oh wow! I’ve never heard of the Powerliner before. Though I wasn’t around in those days to take note of the cost of diesel, it’s hard to imagine that it would have ever been easy to make it “pay off with every payload” with fuel consumption that high… even if you could make better time on uphill grades and straightaways. Then again, I can only make semi-uneducated guesses at what the average fuel economy of average semis was in that timeframe… maybe 4.5-5.5 or nearing 6mpg? 6.5 under favorable conditions?? I’m sure the Hall-Scott gasser in that 1951 Kenworth would drink them ALL under the table, though!
Also interesting that so much of the ad space is devoted to pointing out how special the cooling system is. While it is a very important engineering consideration, I’m more interested in the lead-in photo that’s showing off the sweet diamond quilted interior panels, which were reported to be available in 34 different colors of Nauga’s hide in an ad further down the page. I used to think such upholstery patterns were a bit tacky, especially when installed in a light truck or passenger vehicle, but now it looks totally awesome and entirely appropriate… especially in a big truck from that era. The thought of bright and un-depressing colors actually being on the menu feels somewhat luxurious in and of itself. Schweet!
Well said. The diamond pleated upholstery is very cool and you’re spot on about non depressing colors. I remember these beast well. They have a guttural sound all their own. Truckin like a do da man.🚛💪⛽
Cool truck, but yeah, it’s a shame about its timing. It’s like the ’74 Mopar C-body of trucks, I guess!
The K engines were available in 450 HP, 525 HP and 600 HP. They were heavy and durable. Cummins builds durability. They certainly were the desire of truckers for their power and the sheer pride of having the Cummins logo for the engine on the side of the truck, if your truck manufacturer put it on. They would only fit in long-nose conventional truck/tractors.
Freightliner made it fit in this COE; that’s the gist of this post.
They fit in standard hood 359 peterbilts also with a recessed firewall. I’ve seen every std hood with a kt like that and my buddies heartbeat std hood 450 is like that
I had 1976 STDs hood kenworth 450 5×4 the firewall was pushed in a little bit harder on you legs loved the kit very much
Very cool trucks! I had no idea these existed.
I worked at Cummins for 36 years, retired 6 years ago. Thanks for this article, I learned a lot from it.
Hey what model truck did you drive and is it still around? Do you own it or drove ut for someone? Very curious to hear more. Thanks. -Scott
Sorry I though you said you had a rig of your own and just retired 6 years ago. But as for cummins I’m looking at a genset kt amd I’m in need of alot of cummins parts to make it work in a 359 or any truck for that matter. The last year or 2 of you working at cummins do you recall there still being alot of parts to make a kt long block fit and bolt into a on highway truck? Please text or email me I’dreally like to talk kt talk when you get a moment. 609 500 557four
I sent you a text message.
The fleet i worked for had 4 trucks v12 ddad kenworth dedicated to hauling double 48 ft trailers on i90 in ny 13 speed roadrangers. They came into our shop for drive tires every 12k miles. Back then bias ply truck tires would go 25k on our regular line trucks. But these beasts ate them up in no time
So a set of tires once a month for regular trucks and twice monthly for the Powerliner? Double the fuel and tire cost for normal usage!
The first and second images show the identification lights well off-centre, to such a (variety of) degree(s) that it doesn’t seem like an effect of the angle from which the pics were taken. What is up with that? Subsequent pics show them centred, the middle light aligned with the centre windshield pillar. I mean the group of three amber lights (un)centred at the top front of the cab. It’s not necessarily illegal; the reg requires the lights to be mounted as near as practicable to the vertical centerline, and a bit of lateral offset is commonly seen on the back of box trailers, for example, where the rear gate latch is in the way of putting them exactly on-centre. But why so much difference in their placement on the trucks in these pics?
I’m seeing the effect of the top center marker lights being set back a bit from the front leading edge combined with the camera angle to make it look off center in the first picture.
I don’t see any of that effect in the second picture.
I can’t even begin to imagine why they would be mounted off-center.
We obviously process visual information somewhat differently.
I don’t see any of the effect in the third pic, but it’s prominent in the second—which I can see on my phone, or in Safari on my computer, but not in Firefox on the same computer. That happens sometimes on this site, so I wonder if your second image is the same as mine. Attached are the (real) second and the first image, with violet lines extending the centre windshield pillar upward. When I do that I can more easily see it’s as you describe: the lights are set back from the apparent front, causing the illusion.
I couldn’t see the second one one my Chromebook; I know how to fix that.
There’s a prominent sun visor attached to these trucks, which protrudes considerably forward of the actual roof leading edge. That’s what’s causing you to see it as off center.
I assure they’re not really offset from center. A trucker would never accept that; he would be the laughingstock of the highway. Freightliner would not have done that; Virgil Exner was not consulting with them after he left Chrysler. 🙂
It really is the effect of the visor and angle. I would never have “seen” that because of that angle, which makes it look perfectly normal to me.
Yep, it was the sunvisor what done it.
(Kind of a pity Exner didn’t leave us with any clays for big trucks or buses, eh?)
Cool story, it’s a shame the person writing it kept calling it a Superliner!
Fixed now. Thanks for pointing that out.
Your right. there was quite a few power liners out there. I drove one in 73!/ That my uncle ordered from freightliner but didn’t like the look of it. so he special ordered it as the picture on the right but the radiator was 8 inches thick. As I read one comment about tires if you went balls to the wall in the first 8 gears you could stop and wipe a hard full of rubber off. Kta 600 was an amazing truck. LoL when I blew the doors off the trucks going uphill I always said it was a 300. Cummins. Yes sir 300! On the front half and 300 on the back half.
My dad had a Powerliner with a 450K twin stick 5×4. The engine never really held up and after a few years a 400 big cam went in it. Great looking truck though and about 4.5 mpg was the best it would get.
What caause the engine to not last that long ? I’ve heard then last q mil miles and some only last 100k or so . Any particular reason why? Thanks
You are correct it was KT450 that was available in 1973, the KTA range wasn’t available til much later, still an amazing spev truck but some of these young writers who were not even around when these were king of the road don’t know the difference
Are you suggesting the KTA-600 wasn’t available in the 1973 Powerliner? If so, go back and read the brochure I posted, as it clearly mentions the availability of a 600 hp optional engine. What else would that be?
Totally serious question here: looking at the picture with the cab tilted all the way forward, did O/O’s have to spend an hour cleaning loose change and dirt and cigarette butts from the windshield and dashboard after a major service? Seems like all of your bedding and coffee cups and dirty socks would wind up on the glass…
I’ve heard that, yes, that kind of thing was not uncommon. Maybe find stuff you’d thought was long lost. 🙂
There could be a bit of carnage when tilting the cab. Cleaned out the sleeper in one truck, tilted the cab all the way forward and dropped a coffee mug thru the windshield.
Another time looking for loose items I came across a loaded big bore revolver!
The most legendary one happened at the local freightliner dealer. A lot of truck shops were set with bays on both sides of a central aisle. Door at the back end of all bays. This would give you the length needed if you needed to pull in a tractor trailer unit. Normal use ended up with trucks on both sides pointed nose on to the truck in the opposite bay. There were two cabovers, both with there cabs at full tilt. One was accidentally started in gear and it chugged against the parking brakes and drug itself across the aisle and smacked head on into its mate. This kind of thing would happen occasionally with the big trucks. I would often sit on the front tire with a remote starter bottom to bump the engine over while setting valves and injectors. A well worn Fuller trans will slide into gear very easily.
I am with you on the broken windshield. I had a 1973 freight shaker with a NTC 350 with a 13 that I put 780,000 on before I moved it along.. pulled refer
Saw that several times and did it once myself. Jacking up the cab could knock the shifter into gear.
I hadn’t heard of the Powerliner before, thanks for that Paul. My Dad’s first owner-operated truck was a 1980 Ford CL-9000 with the 600 Cummins (presumably a KTA-600, I had never asked the model). Yes, it would walk away from anything on a hill, I recall riding along with a B-train on it over the mountain passes and it wasn’t a slow trip. And yes it got somewhere around 3-4 mpg as I recall which was why it was replaced with a 3406 Cat powered Freightliner. I also remember the oil changes; 15 gallons (3 buckets) of 15W40 and 3 oil filters.
And a whole lot of grease fittings.
The Powerliner is sort of the ‘Hemi Cuda’ for the 18 wheeler set. Peterbilt had the competing 352H model, also featuring the Cummins ‘K’, Cat 3408, and Detroit 12V-71. It was not as distinctive as the Powerliner, looking much like any other 352 cabover except for its raised cab and additional side entry step.
Those are mighty impressive numbers for an on-highway tractor, almost 50 years ago!
Back then, 350 hp was the top in Europe (Scania 140, introduced in 1969). Anything between 300 and 400 hp was considered a power monster during the seventies and first half of the eighties.
Good write up, with the exception of transmission specs and fuel mileage. I have an 81 pete with a factory KTA600 and 6×4 spicer boxes. Numbers match on the engine and BOTH transmissions. I ran it daily for 3 years, pulling a cattle liner across Canada and the US. I was averaging around 4.5 US MPG with it. Which is a decent number for a flat top with a bull rack. Better than my old twin turbo cat was anyway…
Like lots of info on the web, I wouldn’t be surprised that the transmission info is off. And the fuel mileage is a ballpark.
Thanks, I was just putting it out there, because that’s literally what everyone says. But some times, everyone can be wrong I guess haha. I’ve ran 3 6nz cats, 1 accert cat, and my kta, and with a liner the best one I’ve ever owned did 5 even. So 4.5 with a 40 year old 19 L ain’t bad. And it’s much better than the accent was!
On the subject of large displacement tractor trucks, does anyone have knowledge and or experience of the Isuzu Giga Max?
That is bonkers! It’s totally bizarre, such a huge diesel engine (30 L) and not turbocharged. I haven’t seen a NA big truck diesel engine in ages. Turbo diesels are intrinsically more efficient, as there’s less internal friction. They also weigh less. I’m struggling to imagine what this engine was originally built for.
Paul et al, wondering about the boost level of the Cummings. I saw that the compression ratio was 14.5:1, which is low now, and would seem quite low then. Would this run on glow plugs until the boost built? How high did the manifold pressure get to?
Actually, that’s not low for high-boost turbocharged diesel engines. Naturally aspirated diesel engines had quite high compression ratios (18-13:1 or so), but because a turbocharges forces a much greater quantity of air (and corresponding fuel) into a cylinder, so the actual air density is much greater than in a naturally aspirated engine.
Compression ratio is a ratio of static volume in the cylinder between TDC and BDC. In a turbo engine, the air is already “compressed” (under pressure) from the turbocharger, so it’s much denser to start with. Hence the lower CR to compensate.
Modern turbo engines typically have CR of around 13-15:1.
Glow plugs are only ever needed and used in indirect combustion chamber diesel engines, like the old-school Mercedes and other automotive diesels prior to the mid-late 1980s or so. All direct injection (open chamber) diesel engines start without a glow plug. That includes almost all truck engines going way back, since about the 1940s-1950s, and even then, some had direct injection going further back.
Car engines switched to direct injection starting around the mid-80s. Cummins diesels were direct injection since forever, I think. As were the DD 2-strokes; never needed glow plugs.
Ive got thousands of KMs seat time in Isuzu Giga trucks but not with that engine mostly they range between 400-530hp Ive seen that engine in a different model Isuzu a used import but never drove it.
I had the opportunity to run one of powerliners a few times in the late 80s. It would definitely run. But the company sold it as it ate drive tires and rearends. It was one if the most uncomfortable trucks I ever drove even for a cab-over. To accommodate the larger windshield the dash was lowered knee level and my knees constantly hit the the dash. I only.drove it twice while my assigned truck was in the shop. Sure was glad to get back in my high-mount Pete. Way more comfortable.
What a beast! I never had the pleasure of piloting one, but after a year with a “chauffeurs license” in AZ in 1986 driving flatbed bobtails, I went to work for a meat distributor and they tossed me the keys to a Freightliner cabover single with a 28′ refer pup. No real tractor-trailer experience and my first time with a Fuller Roadranger. It was the night shift, and my virgin attempt at backing it up was in a family-loaded Burger King parking lot at 6pm, off a busy street and through the parking lot, curving around blindside to the back door. Sweat pouring off every square inch of my body and praying I wouldn’t kill anybody, I nailed it first attempt. My heart was ready to explode, but I always felt at home in the C/O Freightliner after that. Thanks for the memories, Paul.
Didn’t need a long hood, i drove a 77 KW regular hood with a KT in it from the factory. My brother was the original owner & sold it to my dad. When he retired in 81 i drove it for him.
600hp is run of the mill here the original truck I was issued with an old 8×4 Sterling lost all the half gears coming home a couple of weeks ago 575hp Detroit 60 under the hood, its replacement is an old Freightliner conventional with 600hp ISX Cummins goes ok but gets overtaken climbing the Kaimai range @ 45 tonnes, much stronger jacobs brake descending though and I fit in the cab better, kinda hoping they leave me in it truck speed ,imit here is 90kmh like most of the world its hills and corners where you make time but on hourly rate whats the point.
600 HP was run-of-the-mill there in 1973? That was the whole point of the article.
I used to see these freightliners back when I started trucking coast to coast back in 1977.i knew they were special and when you seen the big grille you knew they had big power
I was taken aback when in the 2nd to last photo i recognized a shot of the truck in Idaho Springs, CO; in front of Marion’s of the Rockies and King’s Derby restaurants.
In my driving career I’ve been behind the wheel of every diesel powered motor all these companies have produced from Cummings in my opinion not being the best and your reputation of being a come apart and oil leaking like a Harley issues my personal opinion the best ones in my experience at bed between the KTA line and Caterpillar. This mid ’70s cab over we had a KT450 with a 15 speed.
I worked for a company called Brazeau Transport, which evolved into what is now Transforce. Back in the seventies the company had a fleet of Western Star trucks with KT 450’s. They were all based in Matagami Quebec hauling double 45’s up to the James Bay hydro project. They also were equipped with push bumpers as they would help push the 200 thousand lb. loads uphill.
I was working at freightliner sales and service and worked at on quite a few of those trucks they were amazing and they were big
I remember hauling meat to the west coast in the early 80s . Had a 2 story Ford with a Cummins 400 big cam 13 speed . Run across several KT Cummins and 3408 Cats . They would just drive right by you . In the mountains they would fly by like they were empty . Fun times
The KT Cummins was definitely the top dog in the BC mountains back in the day, though the 525 seemed a lot more common than the 600. I knew a guy who ran a CL9000 Ford with a KT to California and back for awhile, but the rig cost so much to run he never really made any money at it. Another problem was weight, that extra 1000 lbs or so came right off the load you could haul. He ran an RTO12515 (15 speed) Roadranger in it and kept it one piece for the time he had the truck but he did say he only ever used full throttle in the top couple of gears, and gently at that.
The 3408 Cat and the 12V71 Detroit had similar drawbacks but that was the price you paid for power at the time. Today 400 horses is poverty spec and even local dump trucks are packing 500 it seems!
When I worked for Peterbilt in the late seventies and early eighties, I don’t recall the 600 being very popular, at least compared to the 540 version, or the Cat 3408 and the 8V92TTA. As someone mentioned in an earlier comment, only minor mods were needed for the KT to fit (and stay cool) in the wide-nosed 359 conventionals, but the 352H cabover (aka “H Model”) used a taller cab and wider doghouse, so while not quite as distinctive looking as this Freightliner, it was a distinct model from the regular 352. When the 362 replaced the 352 in 1982, it was designed from scratch to accommodate the big motors, with a bolt on front frame section that splayed out to provide clearance. This was especially important for the big V8’s and all the intercooler and large diameter intake plumbing these engines required.
These KTs found their way into other trucks too and not as the original maker intended. This is an Austrian ÖAF/MAN owned by Israeli heavy transport specialist Taavura, originally fitted with MAN’s V10 with alleged 450 hp. When said V10 blew up, apparently there was a guarantee dispute between Taavura and MAN which remained unresolved, at which point Taavura said “to hell with it” and had a KT525 fitted. Talk about something sounding “not quite right” as it thundered its way along with that load.
I find the grille’s vague resemblance to a large solar panel, an interesting irony.
I’m always impressed with big diesels of the 70s-80s and their specific power output. Gas engines have always had more HP per cubic inch than Diesels, but in those troubled times, compounded by a sudden correction to real numbers in the early 70s, Diesels passed them up! My experience is with stationary diesels, generators specifically, but since those are rated to run for days if not weeks at a time, they derate them. And they were still over half a HP per inch, which this Cummins monster is. Actually some of my stuff was the big V12s, so likely bigger output than this even. 750Kw is what in HP?
Regardless, when many auto manufacturers were crying wolf, Cummins was just motoring along. Yeah, not exactly apples to apples, more like oranges to tangerines, similar, but not the same. Yes, emissions were part of it, but only part.
750Kw is what in HP 1003hp. 1hp=746 watts.