Hi, I have a side project for my TL in which i'm modifying a Cyl. Head to fit different components from stock parts. One thing I cannot find any information on is valve guides. I'm trying to source some Manganese Bronze types, but without knowing the size of the original ones, it makes it hard to figure out what I should be outfitting mine with. Has anyone changed out their guides? Perhaps have a spare around to measure for me? Thanks.