These help
http://www.summitracing.com/parts/PRO-66003/
there is lotso different types
http://www.summitracing.com/search/?keyword=valve+cover+hold+downs&page=3

I like these gaskets
http://www.summitracing.com/search/Part-...er/?Ns=Rank|Asc
and i like to liberally coat both sides with Right Stuff stick to valve cover then install snug lightly leave over night then tighten.

I don't think 71 heads had hardened seats