These are Harley Davidson cylinder heads for an early side-valve (flathead) engine. These would be compatible with the VLH or ULH engines. The ones shown in the 1st URL link are have inserts in the spark plug holes and fit the 1936 thru 1939 engines. The 2nd URL shows what I believe are the same as yours. They fit the 1940 thru 1952 engines. The 3rd URL shows another version. Harley constantly changed these heads during the years by moving the bolt spacing around and changing the compressor ratio.

These are Harley Davidson cylinder heads for an early side-valve (flathead) engine. These would be compatible with the VLH or ULH engines. The ones shown in the 1st URL link are have inserts in the spark plug holes and fit the 1936 thru 1939 engines. The 2nd URL shows what I believe are the same as yours. They fit the 1940 thru 1952 engines. The 3rd URL shows another version. Harley constantly changed these heads during the years by moving the bolt spacing around and changing the compressor ratio.

References:

https://www.ebay.com/itm/Harley-flathead-knuckle-VLH-ULH-cylinder-heads-oem-o...

https://www.ebay.com/itm/Harley-1940-1952-WL-Iron-Cylinder-Heads-/231949224179

https://www.ebay.com/itm/10-36D-16673-36-Harley-UL-Rear-Side-Valve-Head-OEM/1...