NOS genuine GM engine valve rocker arm.   GM 6255648.   This part is long discontinued.  Original packaging has considerable shelf wear including torn flap and stains.  Bare steel will exhibit cosmetic surface oxidation. Fitment for various Chevrolet Corvair vehicles 1960 thru 1969.  

Check photos for cosmetic concerns before you buy.  Check your vintage GM parts catalog for correct fitment before you buy.