I want to hear of others like myself who are using 472 and 500 in trucks for commercial use - I have a 79 C20 suburban that weighs 5800 lbs- with a 70 500. I'm getting 10 MPG empty or loaded- with 3.73 gears and 31 in. tires- that 14 bolt only accepts down to 3.42- will that increase my milage?? anybody got a killer combo for gas mileage and power? My truck is faster than a 2002 pickup with a 5.3

those 3.42's won't help your mileage all that much...maybe one or two I would guess...I don't think you'll ever find anything better than 10 mpg with that engine...unless you could find some sort of overdrive that would work with it? I've not done any research in this area, so i don't know what is easily available, but it should be possible to find an overdrive tranny that you could make work...would give you better highway mileage, at least...

used to run a 70 472 in my 88 silverado. couldnt keep tires on the back ;)