I would go with the Ford gasket. make sure the block is decked and the head is skimmed so you have perfect mating surfaces.

My first run using the st170/blacktop I never had the block decked and I blew the Cometic MLS gasket after a particularly fast run, the engine always ran hotter too.

I then redid it all with the Ford 1.8mm gasket, decked block and head refaced and its been bang on since.