The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - What kind of gas mileage do you get with your 67-72?

Rich69shortfleet · 10-03-2018, 02:23 PM

69 shortbox fleetside with a 400sb and a TH350 and a 3.73 posi. Best I ever got was 13 but I only ever saw that once as I recall. Typically 10 or between 8 and 10 when towing one of the cars on an open trailer. The truck originally had 3.07 gears and I had the 400 in there for a short while with those gears, but the mileage didn't really seem to change when I upgraded to the 3.73s. I still have those 3.07 gears lying around if anyone could use them....

The original 307 engine didn't really get better mileage than the 400 I have now, but it was pretty tired when I got the truck. The 400 was pretty much a win-win when it went in.

10-03-2018, 02:23 PM	#34
Rich69shortfleet Registered User Join Date: May 2016 Location: Waverly, NE Posts: 445	Re: What kind of gas mileage do you get with your 67-72? 69 shortbox fleetside with a 400sb and a TH350 and a 3.73 posi. Best I ever got was 13 but I only ever saw that once as I recall. Typically 10 or between 8 and 10 when towing one of the cars on an open trailer. The truck originally had 3.07 gears and I had the 400 in there for a short while with those gears, but the mileage didn't really seem to change when I upgraded to the 3.73s. I still have those 3.07 gears lying around if anyone could use them.... The original 307 engine didn't really get better mileage than the 400 I have now, but it was pretty tired when I got the truck. The 400 was pretty much a win-win when it went in. __________________ 1965 Malibu SS L79 Restoration Page 1965 Two-Door Wagon Project Progress Page 2006 Pontiac GTO Preservation Project Rich Cummings Last edited by Rich69shortfleet; 10-03-2018 at 02:29 PM.