I saw this pair of rebuilt early 1500 heads for sale and thought I'd better get them while I could. These don't come along every day. 311 101 371 heads have 40-horse style straight intake ports and were only used through June 1962.
The date code on the casting appears to indicate December 7, 1961.
The heads were apparently rebuilt many years ago and they still retain their long rocker studs. Most of the remaining 40-horse and early 1500 heads out there have long ago been converted to short rocker studs due to the fact that long studs can sometimes loosen and fail to hold torque. Also, unlike short studs, with long studs valve clearances tend to get tighter as the engine warms up, so there's less margin for error when adjusting the valves — a tight valve having much more potential to cause damage than a loose one. For these reasons most long studs were replaced with short studs years ago as a preventative measure. I kind of like the idea of running long studs, though, if only because there are so few VWs on the road that still have them.
The seller believed these to be VW factory rebuilt heads. I'm skeptical about that, though these stamps might back up his claim, as they're similar to some other rebuild stamps I've seen.
In any event, I'm glad to have another pair of early heads on hand just in case. I don't think I'll need them to address my current engine problems, but you never know. Thanks to Eric Colla for pointing me to them.