| Part No. | Models | Year | Description |
| 80009-36 | WLDR | 1937-1939 | Front Iron head [polished] |
| 80010-36 | WLDR | 1937-1939 | Rear Iron head [polished] |
| 80009-40 [set] | WLDR "Special"* | 1940 | Special aluminium heads set for cylinders with valves closer to bore. |
| 80009-39A [set] | WLDR | 1939-1941 | Aluminium heads set. |
*
1940 was the first year Harley-Davidson introduced "tilted valves"
in the W series motor. The WLDR "Special" name that resulted from
this
change is not a factory name, it was commonly used by old timers from the era
and has become the name of reference. The WLDR Special is
the only motor from the WLDR series to use tilted valves. The motor was unique
in other ways: it had special angled roller valve tappets and
angled valve tappet guides that were unique to that motor only.
Extra special thanks to Beachdog for providing this information gathered during more than 30 years dealing with WLDR/WR bikes.