What a cool old truck. Do you know it's history? Was it originally setup as a tractor with a fifth wheel? Is that a 4-71 ? 3-71? Mack rear end! I wonder what the ratio is. The only other similar diesel I remember belonged to a friend. It was a 630 with a sleeper, had a 4-71 and a 5x3 trans setup like that. He hauled furniture all over the country till he got married. Were it mine I'd hunt up one of those low air warning cylinders with the stop sign that flops down in front of your face when the air is low. As noisy as those things are you'd never hear the low air buzzer much less see the warning light tucked way down under the dash.
