Don't recognize this as an O.E. SS 396 Chevelle steering box? You're right. It's from an '86 Buick Grand National, and it almost bolts right into the B-body. You'll need Lee Engineering press-fit flare-seat inserts (rather than the modern GM O-ring seals) for the hydraulic lines and a special rag-joint steering coupler to make it work in the older chassis.