Hard to see and even harder to photograph but I think I got it. The back of my heads are tapped to 1/8” NPT with a 90 brass fitting. Then an AN 1/8npt to -4 fitting. That’s where I install the restrictors. I flat face the fitting, drill and tap for 10-32 x 3/16 brass and drill the size I need. I’ve changed them 3 times to limit the oil more and im at .030 per side now and happy with it so far. On this round I noticed the restrictor backing out so I staked them in as well as blue loctite.
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