I hated mine because it was a non syncro 3 speed.
In 2002 I wanted overdrive and used NP4500's were going for $1,500+. I didn't have that kind of scratch, so I went with a used 700R4. I only spent a few hundred bucks.
Now, many years later I know you can use a T5... wish I had known that then. However, the cabs in these trucks are fricken tiny. I'm only 5'8 and want more leg room. It was a chore to row the gears in my truck (I did it for about 5 years before the auto swap). You have to literally almost lift your leg to use the clutch (and brake pedal). Not fun. I have a 65 Mustang that I converted to a T5 from an auto and the pedals are placed where you just "slide" your feet across. Way more fun to drive.
If someone offered me a free 5 speed swap, I think now a days I would turn it down because the pedal placement just makes it a pain in the ass to drive.
If you look at the history of these trucks... you'll find that many, many, 67's came just about bare ass from the factory. Very few had A/C, autos, trim packages, etc. It was a truck. Some (like mine) were "optioned" with heat. But something interesting started happening around 70/71... compared to 67's, you'll find the vast majority of 71/72's came pretty decently optioned, A/C, autos, trim packages, power disc brakes, power steering. It's MUCH easier to find a heavily optioned 72 C10 than even a decently optioned 67.
Beds were also interesting (ignoring longbeds because very few were sold as stepsides) but when comparing shortbeds, stepsides outsold fleets in 1967 by a few thousand units. It was pretty much dead even in 1968, in 1969 fleetsides outsold steps by a few thousand, and by 1972 it was almost 2:1 fleetside vs. step.
http://67-72chevytrucks.com/vboard/s...d.php?t=104816