Can anyone tell me what their getting millage whise on their Chevy or GMC with a 454 ? The rest of the stuff that might matter: 4:10 rear end, A/T with OD, stock tires 225-75-16. 9 MPG is not good, 20,000 miles on odometer. A freind said he averages 12 with same truck. Best I've got is a tad under 10 all highway.???????

Sounds about right. I guy I know had a 454 in his '99 and he was averaging 10 mpg. I'm sorry, I know it sucks, but thats ALOT of truck.

My 496 gets 9-11. Big Blocks are thirsty motors!

My high school truck was an 89 ex-cab silverado dually with a 454 motor. Yeah, I averaged 8-10mpg. Sorry to tell ya it dosen't get much better.

99 454 3.73 i average about 14

99 2500 8600gvw
454 3.73 its about 14 all around driving

Can anyone tell me what their getting millage whise on their Chevy or GMC with a 454 ? The rest of the stuff that might matter: 4:10 rear end, A/T with OD, stock tires 225-75-16. 9 MPG is not good, 20,000 miles on odometer. A freind said he averages 12 with same truck. Best I've got is a tad under 10 all highway.???????

I am currently getting 8.6mpg on my 98' 1-ton. It has the 7.4L 454 vortech, 4L80E A/T, 3.73 rear, 2WD, and I have upgraded the tires all around to LT235-85 16, rear tires are mud tires and the front are street. The stock tires are LT225-75 16D, which are smaller but have a higher load range. I have also replaced the air filter with K&N and put on a throttle body spacer. Theses motors do love gas but 8.6mpg seems a little much. The best I have got was 11.5 highway between Kansas and Alabama. My Mileage was better in Alabama.

I have to agree with most of these guys. I have a 1999 crew cab dually with a 4:10 rear end and A/T. I get 10 mpg by it self. And if it makes you feel better I get only 6mpg pulling a 21,000 lbs Carrage 5th wheel if I'm lucky. The 454 is a real good pulling engine but sucks gas.