Just my 2 cents. First, I never heard of the 5+1 on the oil deal. The only oil starvation problems with the FE that I was aware of was the 427's at extreme rpm's. That's how the side oilers came about. Second, did you verify that your gauge is correct? I would install a known mechanical gauge and verify what your seeing with the factory gauge. Lastly, the pressure relief valve in the oil pump can hang up and blow the filter off on any motor, I've had it happen to me twice. Once on a buick v-6 and another time on a dodge 360. So it's not all that uncommon. Heck, we used to add shims to force the pressure higher! Hope this helps some.