1966 c20

[d-carl]

Hello,I am new to this forum,but not to chevy trucks,they make up most of 30+ years of driving,always one behind the shed,or in the yard,the other morning when I got up and looked out I seen another took up residence,so while doing a little research on it I found this site,I plan leaving this truck much as it is,with some upgrades in suspension maybe others,I have not had but one other this style that was in the middle eighties,the first thing I will look at,will be which motor I will run,small v-8,or 250 6cyl,it has a 4-speed truck trans,I not sure of trans and rear end gearing yet,what is the average gas mileage for these trucks with these set-ups,stock engine,has anyone swapped the stock trans for a newer 5-speed out of a car or truck,thanks that is enough for now I will check back later,