In my 35 sedan, I used a pair of buckets from a ford fairmont. They were low back, thin, and narrow seats that were actually fairly comfy. Even the fairmont seats sat side by side, you had to be friends with whoever was riding with you. Tried seats from a front drive Mopar, but they were too high of a back and too wide. In my 54 pickup, I used a bench seat from a 4 door valent, it was narrow and set just under the rear window ledge. That 54 was a bit wider then the 30s cab would be, but there was still room on both sides of the valent seat, it might still fit. My 50 truck has an unknown set of buckets with the adjustable seat backs, those work out well, you set the back angle which lets you move the seat farther back. Gene