International Harvester V8 gas engines

I’m talking about the 304, 345, and 392.

These motors were stout torque monsters rivaling diesels of the era, durable, dependable…and absolutely thirsty gas guzzlers.

Was this because it had a big cam profile? The strange valve layout? (looks like an inverse hemi)

Would retrofitting a modern EFI meter fuel more precicely for improved mileage?

it’s just a canted-valve design, similar to the Ford 351C/M/400 and 429/460. they weren’t “torque monsters” in any real sense; they (like most other low-revving truck engines) just made fairly low hp numbers for the engine’s displacement.

quite the opposite; these kinds of engines have “small” cams with lower lift and shorter duration. the lower valve lift contributes to better low-rpm mixing and turbulence, improving throttle response and low-rpm drivability. the trade-off is that they run out of breath by about 4,000 rpm.

the reputation for being fuel thirsty likely has a ton to do with the vehicles they were tasked with pushing around. big, heavy, non-aerodynamic trucks. fuel injection would help a bit, but not much if the engine still has to power a vehicle which is harder to push down the road.

Heavy for the amount of power it generates (which is why they were so tough compared to a modern car engines), and probably linked to a gearbox which requires a large power range.

Torque monster can be made in the gearing instead.
An old 35hp Fordson tractor can make enough rear wheel torque
to pull a new shiny diesel pickup truck with a lot more engine into nice little pieces.

All in the gears

The bore and stroke is larger and longer, the compression is low.

Longer strokes= high torque at lower rpms and comparatively low efficiency (in an automobile).
Approximate V-392 specs using more “modern” net measures:

Brake H.P. (Net): 191 @ 3600 RPM
Torque (Net): 307 Ft. Lbs. @ 2400

They weren’t “torque monsters” as state above, they were just rated at a higher duty cycle with a longer stroke than other brands at the time. Almost any LS will better HP, torque and longevity than these old motors.

We swapped a Detroit Diesel 6V53 into farm truck back in the day, and it was an incredible improvement. But a LS would be far better bet these days.

The bummer about the good old days, is that they weren’t.

how long did it take for your ears to stop ringing?

Hm, 345 in a 79 Scout 2 got 20 mpg, which was pretty common mpg at the time, and a good dependable truck.