What is every one getting for fuel mileage with there 400's? And what rpms should i run at about 65 with 3.54 gears?

 

I get about a weeks worth of driving. If my odometer worked I'd have a better idea. When I drove it home the day I bought it I used my gps to track miles and I got just over 11 mpg. That was running around 60-65 mph. That was a long trip. with 4.11 gears it seemed like my rpms were screaming. Wish I had a tach.

 

My 77 F150 gets 13 mpg at 60 miles per hour. Off road it gets about nine. My engine has 10.5 compression and a modest roller cam. 4.11 gears and 33" tires.

 

10-12 usually.

 

A stock 400 ?

 

With the DEH-255 cam kit, headers, 650 cfm Holley, Eddy intake fresh fluids and filters and in overall good mechanical order, I can pull 14 hwy and 10 city. That's my go to combo in all my rigs.