The trick is to use the holding down tab washers from the later Pinto engine under the rocker box screws.. These prevent the rocker box distorting.
A smear of gasket sealant will do it no harm and there are no oil ways nearby for it to clog up.
I use Hylomar Blue and apply it sparingly with a kiddies paintbrush. Comes off easily with cellulose thinners or scraping with a Stanley knife blade.
Ultimate way around this would be to move to an alloy rocker cover but they are pricey - but they do reduce the clatter from the valve gear!!
Arwyn
