I had a pickup that looked just like yours several years back, i bought it thinking it was a truck, after the purchase and putting it on the lift to check it out closer, i realized it was a 62 body and bed that had been drafted on to a 70's transam frame, suspension, motor and trans. It was alot of fun to drive!! and imagine that it, it handled like a muscle car. Ended up finishing the paint and selling it. I should have kept it for my collection.
what reminded me of this truck is when you mentioned your tranny, my truck had the same tranny with a car stick, i remember always having to reach way down to shift the transmission, made for some sketchy cornering at high speeds.