RE: Injectors:
The original pump for the Hilborn Ardun injector was a vane type that Stu stopped making or servicing many years ago. It is extremely hard to find one in good working condition, so most folks who happen to have one of these injectors will use a modern pump. Here is what the original pump looked like - you can see the pressure relief valve with the tie wire on it. Modern pumps don't have pressure relief valves in the pump - they are part of the line/plumbing instead (and there are many ways they are implemented) - depending on the injector style, usage, fuel type, etc..
Here is one of the early Ardun injector pumps I have:
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