318 Heads: bad valve job?

Again, Machine Work all depends upon the application.

As for Valve Guide & Seat Machines,

Back in the day it was the 'Winona PH-2000' that most of the performance shops
were going with.

'Specialty Shops' who were banging out Cylinder Heads like McDonald's sends out
hamburgers, it was 'primarily' the 'Tobin-Arp VGS'.

As for the 'standard shop', many went with the 'Kwik-Way #020', which was lighter than
the 'above' mentioned Valve Guide & Seat Machines, but was good for general machine
work.

A 'Bridgeport Milling Machine' with a 'J-Head' is a must for performance shops, but
for general work, it takes too long to set up, unless you have a modified base
to mount the cylinder head.

The 'Peterson Machine' started to make a play in the early 1980's, and was a good piece
of equipment, especially if you were doing 'Heavy-Duty Work' and 'Diesel Heads'.