Cylinder Head Part Number is 040.101.3732 with a 2BR and a 51. The valve diameters are 33 and 35 mm (+/-1mm). That is all i know about these heads and the fact that they have been sitting for many years. They look new but idk. 1600 cc one cylinder. I was told they are probably a 1960 ish VW. Asking 150.00 as i researched similiar heads on Ebay and they were much more than my asking price. If interested please text Andrea at: 707 247-8820.