,820 is dead on 1/2" BSPP and not close to anything SAE. If that is the plug out of the N port you have a real good chance a P40G PB sleeve from Summit will work in your valve - $21 and free shipping.I measured that wrong.
The depth of the hole is very close to 1"
That's bspp 1/2 right?
I'm not sure it's sae. I tried to screw in a 1/2 bolt in there and the thread doesn't match
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