Speedmaster Small block porting tips and results Part 1

Hemioutlaw said

? Are you referring to .050 TIR on a seat that was precut and THEN installed in the head, .050 TIR is a Football field of runout.

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I'm thinking TMM was suggesting that rather than use a pilot in the valve guide to machine the seats, they were somehow piloting off the OD of the guide.

That's the was I understood his question but I could be wrong about that.

I have seen several valve jobs with .050 TIR. They were all BBC's with 2.400 valves and .311 stems.

Just junk crap.