I have two oil pumps, one is off my L26 and the other is off my old L20B. The question is about the casting marks on the two of them. The one off the L26 has H23 cast in it and the one off the L20B has H33 cast into it. Are they the same pump and these are just cast numbers or does it have something to do with volume pumped?

Probably a stupid question, but if someone knows the answer that would be great.

I don't have an direct answer but at a guess I'd say it relates to how much they can pump. The L28 Turbo is the best pump for a Z and I'd say although I have to check that the cast number would be different again.

Maybe someone else will know for sure?