Mike you mention the block is a "old solid lifter engine". Are the lifter
oil galleys drilled and plugged or has the block never had the
oil galleys drilled? The rear cam plug boss will tell the story. If the cam plug has two plugs or screws to the upper left and right of the rear cam plug it's been drilled for hyd lifters and most likely plugged inside the lifter valley. If there are no plugs to the upper left and right it's a true solid lifter block. In that case a hyd roller lifters could be a problem. There was a very good recent disscussion on the FordFE.com site about the pros and cons soild rollers in a soild lifter block. Pg 4 over there.
BTW are you building another Hurricane?
G.