...Were All the Valves Lapped-In By Hand!!! Before Assembling in the Head??
NO Power Drill! IT Influences the alignment and It Wears the Valve Guides, Oblong! It's simply Too Fast! The Guides are Not there for the Valves to be spun in them, only a slight rotation during operation. It is Not as accurate as Lapping by Hand.
If The Valves are already Installed in the Head, You Disassemble The Valves. Every one and Lap them In, By Hand ONLY, Slow, Reversing and Accurate.
I Did!! Just use the FINE Grit. Do Them All and Make sure they get back in their matching Bores
...If a Exhaust Valve doesn't seat, You're Burning a Pathway through the Seat! An Explosion is Not going to seat It!
In My Opinion.
MJ
P.S. In the Above Photo, is That the Decklid Sitting On The Roof?? NOT a Good Idea, Even with Protection, The Weight of it, over Time, will Leave Marks, that can not be Easily Removed! Glad To see you have some protection at the 'Tail'.