Well I like to think I research things very thoroughly before doing them. And here is the FACTS that I found from MACHINISTS on this subject and I apologize I don't have the links handy but here is what the consensus of several machine shops said.
1.) after checking valve to piston clearance on countless heads they found the head has between .007-.009 to deck and be in the safe zone.
2.) the guys who did proper machined work on the SERVICABLE heads with a proper surface finish never had an issue to report.
3.) machinists who took heads down past safe zones because of warp machined and shortened valve stems to give proper clearance. Never had an issue to report.
That being said some of the main issues with powerstroke heads is cracking at the seats. Proper cleaning and a straight edge just won't fix that. Another is warped castings especially in over heat situations, same theory applies that you can fix that with cleaning or a straight edge. I don't know about anyone else but putting a cracked or warped head back on my truck would, well, not happen.
So in my case I had mine magnafluxed and no cracks. One head needed .003 taken off to be TRUE flat and another .004. The machine shop I used put the same surface finish as a factory head or reman head has. To this point the fact is I have had no issues, the machine work cost 175 bux I gave him 200 cause I am ballin LOL. Save myself the better part of 2 grand on machining vs buying new.
So my question to everyone who thinks I did this all wrong and should have bought new, the same machinists on that same forum also measured a handful of remans right from ford, NOT ONE .... AGAIN NOT ONE was flat and some warped too bad to even use. So if these guys at ford and international are so good at what they do why can't they send out a REMAN head that is friggin flat. Did they nix the QC department??? A new head would scare me more than taking a couple thousands of material off to make the head dead flat.
Any how I will report back if I ever have a failure because of machining my heads
2005 Harley F-250 CCSB
True Blue Metallic
Engine: ARPs, OEM oil cooler, Bed plate reseal, OEM HGs, Stand Pipes, Dummy Plugs, STC Fitting update, Bulletproof EGR, Rotella Ultra ELC, Sinister Coolant Filter, Machined stock heads, Blue spring
Exterior: Nitto Terra Grappler 295/60/20s on stock Harley 20s
Interior: Edge Insight CTS w/ EAS Fuel Pressure & EGT
Trans: PI Stallion, Billet input shaft, new clutches, 08 pan/filter