Hylomar and MLS
 

Anyone used or know anything about using a sealant on HG to help with poor block deck and sealing?

No. As long as the block and heads are flat, there are no issues. The stock MLS gaskest as well as the black onyx/victor reinz are very good gaskets. The big issues is having those heads flat.

Yea I bought a set of used 2007 MY heads from a guy down here, took them into a machine shop, been pressure tested, magna fluxed, vacuum tested, decked and a valve job on each. One head was out 0.008 and I know that is the max you can take off, but then the guy said the valve stem length could be adjusted some and the do it all the time with no problems. Anyway, I pick them up tomorrow and I have them ready to go on when I tear it down after the 1st. My main concern now is getting the block deck surface right, and I am curious what the max allowable it can be out and still work? I have been doing a lot of reading online and even thinking of getting a top side creeper for this work.

I'm unsure of the block specs. You might be able to call Ford and figure it out as well. Sounds like you're off to a good start though. I'd just put the studs in and let her rip! Are you using ARP's? New lube?

Yep Re-using them with the new ultra torque lube. I don't really like Ford much as they did the HG less than 30K ago and I did not know any better on what a PITA these 6.0s are. Other than that have all the parts lined up...