The codes WH, WI, WJ, and WK are interesting ones since they were all used on three different engine sizes:
1965 283 ci
1966 283 ci
1967 283 ci
1968 307 ci
1969 350 ci

All were in trucks...however, the 1969 WI code shows to be used in P bodies only in 3/4 ton and 1 ton versions, 350 ci and 255 hp with single 4bbl carb and manual transmission (LS-9 engine option). A "P" body is a step van or an RV chassis.

A WJ code in 1969 was the same LS-9 motor with a powerglide in a Series 10, 20, 30 with a C body (2 wheel drive).

A WK code in 1969 is the same LS-9 motor with a turbo 400 also in a 10, 20, or 30 series with two wheel drive.