ISX exhaust valves leaking oil

[BlizzardGuy]

Pretty much what I expected!
The whole job was a pretty slippery sh$t slope to begin with
Is there an obvious way to tell an aftermarket head from an OEM one?

Also the questions regarding crankcase pressure -- this crankcase is vented straight to atmosphere and it doesn't seem to have an abnormal amount of blowby.
I distinctly remember having one look at that engine when it was still bolted to the shipping crate and telling the customer "Now's your chance to send that back and get a proper engine". .. .. The regrets he must feel now for trying to save a buck

Nonetheless, I like the guy, and the only option on the table is a complete long block from Cummins with WARRANTY!!