I have the ARP studs with the allen key holes, so no problems. I did have the clearance the Hooker 6901 header flanges in a couple places to make room for the nuts. But studs do a better job of clamping.
While studs can help with overall load clamping consistency(through fewer friction points during assembly).. to some degree(not nearly as much compared to using premium bolts in a well prepped/lubbed block).. decent quality bolts along with good high end head gaskets will be much better money spent in the long run. In fact.. I'd usually opt for cheaper bolts combined with nice MLS gaskets.. than nice studs combined with cheaper Fel-Pro composite gaskets. And for those aiming for overkill.. premium studs combined with MLS gaskets will take almost any level of power. In general.. most engine builders know that studs are typically best used to prevent wearing/pulling the threads out in the block of racecars that see repeated/consistent teardown/reassembly.
I've found that Felpro's O.E. expanded graphite gasket seals better'n just about anything. The graphite when compressed adhere's to both iron and aluminum better than anything else. I used them on my 331 9 years ago, they're still doin the job. I copper kote em for extra insurance before assembly.
Yeah.. I can easily beleive that. The OE stuff has improved immensily due to the trickle down effect of areospace, racing, and even industrial use equipment. The warranty work involved with the auto mfgrs slow trial and error process has also lead to push for much improved sealing alternatives as well. I usually prefer MLS gaskets whenever.. and wherever.. possible.
Yup, you don't just peel these off after pulling the heads. They'll stick to one side of the other (or both) then it's the ole, "razor blade scraper and wire wheel on the drill time" in order to get the rest off the decks. I tried the Felpro P.O.S (Print-O-Seal)gaskets with these heads first, they sealed for about 3 months before letting go when the engine ran hot the first time. The graphite ? you can overheat it all you want, they never leak.