Hi, I'm doing up a 202 head with porting and chamber work and valves similar size to a 12g295. I plan on getting a set of appropriately sized HSS cutters and doing the job myself (not installing hardened seats). The question I have is what size "exactly" does the pilot shaft need to be? I initially thought a diameter of 7.1mm which would give me 0.0017" clearance but advice on other forums has said that will be too loose. Should I go 7.14" as 9/32" equates to 7.143mm. I guess a very neat fit after the guides have been reamed will be ok as it will only be spinning slowly by hand, say less than 0.001". Thanks for the advice, and yes I know I can get a pro to cut the seats but I want to have a go anyway, cheers.

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1972 Mk3 Mini 1000, 1150cc supercharged.
https://www.ausmini.com/forums/viewtopic.php?f=3&t=95872