Permatex ultra copper for most gaskets. Cover the mating surfaces with a thin layer; tighten the bolts; and wipe off
the excess with isoprophyl alcohol. osengines.com is the source for most OS questions. Some parts are available,
many are not. Almost any part shows up eventually on Ebay. Hopefully someone out there will send you a copy of
the manual. All I have H60-FGP and -FGR which are older and different. OS has some copies of older engine
manuals - see their web site.