should i use felpro or motorcraft exhaust manifold gasket on my replacement?

 

I'd say oem.

 

I would buy one of each. Compare. Pick the one I liked the best. The OEM might be very reliant on perfect surfaces as machined on the line, while the aftermarket might be aware of imperfections that can develop, and take them into account in their design.
I know many FoMoCo products do(did) not use exhaust manifold gaskets as assembled, but depend on the machined surfaces to seal well enough.
I think I would likely go aftermarket, as the OEM gaskets have had their chance, and failed already.
tom

 

Felpro is always better than OEM

 

I was hoping. Mine failed in three years (felpro)

 

My OEM is 11.5 years and 292k miles.