I have a picture in my mind that the Jerry can could slip in alongside the seat and angled toward the hollow of the cab door frame. I’ll have to look closer and measure next time I’m in garage. I have original bench in my ‘57 3200.

1957 Chevy 3200
Daily Driver
PS, A/C, Tilt column, Rebuilt 350, Rebuilt TH350, Reupholstered Bench Seat, sound proof/insulated, LED headlights/taillights/backup lights/interior courtesy lights.
Follow in the DITY