It looks like someone has attempted a sealbeam conversion. I understand that when it is done, the adjustment within the housing is lost.

I remember the post you are asking about. They glued a modern socket from a car into the headlight reflector.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!