[71_C10_]

Hello all!
My goal is to install a manual transmission into my 71' C10. It must have an overdrive as i do a good amount of highway driving and I like to cruse without hearing the engine scream. Currently, I have a 700r4 in the truck paired to a built sbc 350. My question is, what transmission should i go with? I am mainly looking for something that i can find from a junk yard or craigslist. I assume, depending on the transmission, that i will have to purchase the appropriate bell housing.
Thanks!