Anyone tried these?

http://www.federalmogul.com/FEDERAL-MOGUL/Templates/Template_E2.aspx?NRMODE=Published&NRNODEGUID={A539CB26-840D-4889-A87E-98746FFFE107}&NRORIGINALURL=%2Fen%2FAftermarketSolutions%2FSouth America%2FSealingSolutions%2FProducts%2FLeakRepair %2FFel-ProValveCover%2FPermadry%2F&NRCACHEHINT=Guest

I just did mine with standard ones bought from local parts shop, they are fine...