My 82 K20 stepside gets between 15-22 mpg,(6.2diesel)in mostly stop and go and urban nightmare traffic,I havent gone on the highway with it much yet,at least for any distance,til I get better tires and upgrade my tranny lines,and find out why it wont come out of 4hi--mileage might get better when I can put it in real 2wd,and not have all the shafts turning with the hubs unlocked..all in all,pretty impressive mileage for a fairly heavy 3/4 ton pickup--a K5 might be lighter,and get even better mileage.You can get away with higher gears(or bigger tires without a gear change)more with the diesel,they like to pull,at lower rpm than a gas motor,they dont like to wind out,the govenor will let it get up to about 3600 rpm or so--hmmm--same rpm my briggs and stratton lawnmower tops out at! /forums/images/graemlins/thinking.gif /forums/images/graemlins/rotfl.gif