mileage motors

[streetstar]

Kind of a funny topic under other circumstances, but this is a forum board full of people with 10 mpg vehicles. I like to drive my truck more than let it sit, and was wondering if any of you remember if the 305 Chevy motors from the mid '80's had any special cam grinds or anything that helped them get decent mileage. My '84 with an OD tranny got 18-19 bone stock back when i was in high school (late 80's) ---- My '06 F150 doesnt even get that good.

Anyway -- what tricks do i need to know to build a replica of my '84 setup for a '75 C10? I have a stock 305 motor from that era, but i suspect most of the efficiency came from the overdrive tranny, which i am willing to pony up for, but i am wondering if i need to use any special cam profiles or torque converters or anything.
(i will be pissed if i spend $1500 and take 100 hp's away from my truck to go from 10 mpg to , 12 or 13)