maxpat82

used my truck for a couple of month (~4000miles) with a leak.
put a dorman replacement and everything as been fine since (2years)

bwFX42006

I'm torn between replacing with dorman, or going with an OEM FORD manifold. The dorman is cheaper, but that's not always better...

Dfedx

I replaced both manifolds on brand new rebuilt 5.4 and after 4 months the passengers side is warped.
I pulled a trailer twice and that's the only way I may have had any wear on the manifold.
not sure what gasket was used yet but will find out.
rumor has it that the passenger side manifold commonly goes.

Eric Kleven

If you're worried, get some ultra-high-temp gasket sealer and put on it.