No "jig, no "bolting"
Goodway (among others) has expanding pilots that co-ax in the guide, and carbide cutters that slip over the pilot.
A GOOD hand can power them by hand, or you can attach a drill motor.
This tooling was common fare, back when the flathead was the rule, rather than the exception, and "In Frame" overhauls were common..
I'd venture the seats that you THINK need "cutting" would deliver fine service just lapped.
You're win-win regardless,.....and if your "valve Guy" tells you you need to pull the engine , he's a confused idiot.
GTC
