Truckstop Classic: 1966 International R190 AWD Truck – My (Enduring) Lust Object

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– Posted on May 29, 2022

(first posted 4/27/2011). Nothing beats a helping hand. Summer is around the corner, and some four years of procrastination and denial while writing for TTAC and starting CC have caught up with me, so I’m going tackle a big list of building and maintenance projects on my little fleet of (usually) immobile Curbside Classics. The key to making it possible is help: thanks to new contributors, CC will keep rolling while I cut back my desk time.  Now my poor old overworked ’66 F-100 could use some help too, like a big brother of sorts. Here it is:

It’s got everything the F-100 doesn’t: all-wheel drive, a dump bed, serious load and towing capacity, and lots of gears to play with. But it does share one thing in common with the Ford: a straight six, although quite a bit bigger. The International L and R Series trucks and their Red Diamond big six engines were legendary in the fifties.  In the era before long-haul trucking really took off, they were one of the most significant players in the big-truck field, taking on every demanding job and in the process creating a reputation that made International the biggeat truck maker in the land.

The L Series arrived in 1950, and except for some of the really huge “West Coast” rigs, defined the modern big truck of the times. The sleeper cab version above is pretty representative of long haul trucks of the eastern half of the country, when severe length and weight restrictions on the old two lane highways make these semis look like toys compared to modern giants.

The L Series, which was replaced with the very similar R-Series in 1953, came with a new family of big sixes, the Red Diamond big block. The first version had 372 cubic inches, but larger variations appeared in 406, 450 and finally, even a 501 cubic incher. These gasoline engines were revered for their fat torque band and toughness. And there’s nothing quite like the sound of a really big gas six, working hard. Either you’ve been initiated into the cult, or your time hasn’t come yet. Better hurry; big truck gas sixes aren’t exactly getting more common.

Of course I appreciate a diesel’s inherent efficiency advantages. But except in the newest ones, their tremendous noise and vibration levels are an assault on my poor old ears. And there’s another thing: diesels inherently have a very narrow power band; often just 400-600 rpm. Gasoline engines have a much broader power band, and are really much more pleasant to drive in typical situations. Of course they suck more fuel, but back when fuel was dirt cheap in the fifties and sixties, truckers were very resistant to giving up their big gas engines, and for  good reasons.

Let’s take a look at this legendary engine. This particular truck has the RD406 engine, as the block plate makes clear. By the time this truck was made, it was making a mighty 193 hp, probably at about 2800 -3000 rpm. Now we usually think of straight six engines as having very restrictive log-type exhaust manifolds, but not the RD. Check out these nice cast “headers”, and the genuine dual exhaust system. These big engines had to breathe in order to put out the kind of power required of them, and it’s evident from their plumbing.

Interestingly, the exhaust ports are all individual, but the intake ports are siamesed. Reducing exhaust back-pressure was an obvious design priority.

I didn’t properly take it in when was shooting, but this rather unusual big two-barrel Holley carb doesn’t seem to have a float bowl, as this is a propane-fueled engine.

The other side: well, it shows off the big six’ nice lines, eh?

This particular R-190 has a somewhat interesting provenance. The R Series was mostly replaced by other more modern IH trucks, already by the late fifties. And by the sixties, International had diesels as well as a new huge gasoline V8 engine. So this 1966 R Series is probably one of the last years it was made (this ad is form 1963).

But certain customers still preferred the R Series, especially public agencies like highway maintenance authorities and utilities. This one appears to come from the Gregory South Dakota Rural Electric Cooperative, if I’ve deciphered the fading door sticker correctly. Utilities and public agencies were more interested in a rugged truck that would last them in their low-mileage use for decades, than the latest and greatest over-the road machine with maximum efficiency.

And for those muddy ditches in SD, AWD is the way to go.

The beefy front axle on this one is a thing of beauty, no?

The rear axle looks hefty too. Twin sets of massive leaf springs on each side; the upper set only comes into contact and use when the load gets serious. Still, this is not going to be a plush-riding urban-cowboy pickup. Looks like the brake lines have just been replaced.

The L and R Series cabs were none too big, but had a rep for being particularly rugged. One operator said that the R Series doors were the best in the industry; they never went out of alignment and became hard to close, despite the grueling punishment. Those are the kind of details that make a legendary rep.

I’m ready to slide in, fire up the big six, and roll down the road with a load of whatever in the back. Hook up a rental trailer with an excavator on the back (I used to pull them with the F-100, but I just don’t have the heart and guts anymore).  Pick up a load of gravel at the quarry…

Back to reality…I don’t even know how much the asking price for this truck is, and I know I’m better off just renting a dump truck by the day when I really need one, even if it is a diesel. Well, the new turbo-diesels do have a nice little bump in the torque curve when the boost comes full on.

But I can let have my few hours of longing, and try to get it out of my system by writing about it. That usually works for all the other vehicles I write about.