350 to 454 engine swap

[1981Cheyenne]

hey, I blew the 350 in my 81 chevy half ton stepside 4x4 and was looking at buying a 454 and was wondering what kind of gas mileage I could expect.

anybody had a similar truck with a 454 or know what I could expect?

thanks.

[1968 Pontiac]

I get around 10mpg with my 89 K3500 RC/LB with stock 454 and 4.10 gears. I have another 454 which currently isn't in a vehicle, but when it was, after it was broken in, I was getting 16mpg city driving with 425hp in a 73 Chev Caprice ragtop. That was around twenty years ago when 5 liter mustangs were fairly new; the only thing they would see was my back license plates 'cause they couldn't keep up. The only street cars that were faster were Buick GN's. I lost to one of them once and one of my buddies did too. He had basically the same engine but in a 67 Firechicken. Anyway, if you can, do the cam, intake , headers, ignition, etc., you should get better gas mileage. I had another 73 caprice ragtop where I modified the stock 400 SB engine with great results. I was getting 10mpg when I got the car, did the mods with a mileage cam and got 20mpg, and it would spin the tires shifting gears after I threw in a shift kit.

[1981Cheyenne]

thank you very much.