440 rear main seal... thoughts

Good idea but I think you need oil pressure and the crank spinning to show it it truly leaks.
Here is what I do to check to see if everything is good.
Install the crank, lower seal and main bearings and torque everything down. Put white grease where the seal rides and turn the crank. I’m looking for a pattern that is 1/16” wide. Then I pull the crank and seal out and just put the seal in the retainer and repeat. If it is also 1/16” wide AND the upper and lower seal make contact in the SAME place on the crank you sould be good. One more thing, apply a small bead of “The right stuff” on the back side of the seals and on the seal ends where they contact each other. I also offset the seals in there saddle to make sure that there lined up as well. This is what works for me. Hope this helps.
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I had real issues w/ my stock 440/505 seal, ended up finding the rear seal cap was machined off center on the \bolt holes , was off center when bolted down , none of the above would fix it !