Vintage Truck Photo of the Day: 1968-1972 Chevrolet C60 Medium-Duty Tandem With 427 Gas V8 – The Corvette of Semis

This vintage snapshot of a Chevy gasoline powered semi truck is rather fascinating, as it’s a medium-duty C60 with a sleeper cab in the role of a big semi truck. It did have a bellowing 427 V8, which had plenty of power, but wasn’t exactly fuel efficient (2 mpg at full chat?). This rig is something of a throwback to an earlier era, when medium-duty trucks with gas engines were quite common as semi trucks. But by this time, that was not so much the case, as heavy duty trucks with diesels were increasingly dominating the semi truck market.

Almost certainly this truck wasn’t in typical full-time long haul use, but more likely hauling perishables from farm to wherever, probably seasonally. Who knows for sure?

The medium duty series topped out with the C60, and in 1968, a new 23,000 lbs rated rear axle allowed a GCW (Gross Combined Weight) of 60,000 lbs.

I should point out to those not in the know that the 366 and 427 Chevy Mark IV truck V8 engines were not exactly the same as those used in Corvettes and such. The biggest difference was that these were tall deck engines, meaning the block deck height (top of block) was higher, so that longer pistons with four piston rings could be used. That improved durability at the constant high loads these engines were subjected to.

These are referred to as “tall deck” 366s/427s. And there’s other differences of course too, from sodium filled exhaust valves to heavy duty components all-round, and of course the accessory drives are set up for truck use, for air compressor and such. The Holley four barrel has a governor, which works off the mechanical advance distributor, limiting max. revs to 4000. These were of course tuned for maximum torque and continuous power output, and at full chat, exhaling through two big short pipes, they were somewhat famous for their vocalization. And their prodigious thirst.

But with a real 230 hp on tap, as much or more than a DD 6V-71, they could move a load right along.