Hi.
I've used these
Ford Racing M-6582-F302 - Ford Racing Aluminum Valve Covers - Overview - SummitRacing.com stock height covers with 0.2" rubber gaskets, 0.6" valve lift & 1.6 ratio (Comp steel) RR's. No problem.
However- when the RR's were replaced with Jesel shafts, it was a tight fit... I had to grind off some "warts" (some kind off threaded pidestals for shielding cover) and give the splash shields a couple of bangs with the hammer. Worked well in the end.
RS