my new truck and a question

[kbar]

Hi,
I am new to the classic truck world. I am currently overseas coming home soon and I happened to come across a good deal with this truck. I attached a few pic of it. It is a 1975 C-10. I have always wanted to own a C-10, now I have one. Of course we all have plans for a truck probably before we ever buy one and I do, and it is the usual, wheels & tires, exhaust, and drop.

But my main project. I love the sbc 350 because of it's versatility, but as the same time I will drive this truck when it is too cold or rainy for my motorcycle. I've heard some horror stories of carbureted engines not being very dependable and bad mpg. I have read a few post, magazine articles, etc of how to improve mpg.

Now to my main question I have a buddy who offered to sell me his 400 small block chevy out of a 2002 chevy truck that has a 4L80 transmission(4x4), all the wiring gauges, and whatever else that I would need for $1700, or do I take $1700 and put it into heads, cams, exhaust, etc? I would like to have around 12-14mpg with the most performance I can get out of it before sacrificing mpg.

Or what else would you guys recommend?

Thanks,
K-BAR