And to further clarify...
The engine number and displacement is stamped on a raised pad on the passenger side of the block just below the front of the exhaust manifold casting.
The chassis number (most important for replacement part number applications) is stamped into the "face" of the driver side frame rail (very small font), somewhere between the front and the rear of the exposed frame rail as viewed through the wheel opening. Much cleaning of the frame rail will need to be done in order to find the number.
From model year 1966 through model year 1972, ihc used a 13 digit serial number unique to each vehicle. Beginning with model year 1973, ihc changed over to the federal-spec 17 digit "vin" (vehicle identification number) developed by the sae.
Since your vehicles is a '79, then it has the federal 17 digit vin number assigned at the point of manufacture. The vin incorporates the chassis number as part of the code, the last 6 digits.