Cracked Valve Guide Pillars - OK to Use?

I was surprised how inexpensive this valve job had been, ~$90/head, which included repairing a few small cracks.

The heads would never have left my shop looking like that.
But then again....... they would be considerably more expensive than $90/head.
A lot of what machine shops charge has to do with what region they’re in.
I started in this business in 1989, and the shop I worked at had a basic valve job(disassemble, cleans heads and parts, reface valves, grind seats, reassemble) on a V8 at $100/pr.
The owner had it as a “loss leader”.
It was a huge loss.
I ended up managing that place at one point, and immediately did away with that loss leader pricing.

It’s pretty easy these days to have $1000+ tied up in reburbishing a set of 40-50 year old iron heads.

And that’s before the porting happens.