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

Accelo · 02-08-2021, 03:17 AM

369 with THM 400. 10 on the highway. 3/4T with 4:11's.
Same motor with a 700R4 mileage went to 13 on the highway. 30% improvement.
Would only do 95 in overdrive. Any more throttle and it would kick down into 3rd.
Missing one passenger mirror after the experiment. I know the transmission could have been modified to pull full throttle in overdrive. I only attempted this once and as such I didn't care.

Didn't change much in town. Just crappy mileage like always.
Rick

02-08-2021, 03:17 AM	#104
Accelo Registered User Join Date: Mar 2015 Location: washington Posts: 2,165	Re: What kind of gas mileage do you get with your 67-72? 369 with THM 400. 10 on the highway. 3/4T with 4:11's. Same motor with a 700R4 mileage went to 13 on the highway. 30% improvement. Would only do 95 in overdrive. Any more throttle and it would kick down into 3rd. Missing one passenger mirror after the experiment. I know the transmission could have been modified to pull full throttle in overdrive. I only attempted this once and as such I didn't care. Didn't change much in town. Just crappy mileage like always. Rick