If you are talking about the port right on top of the oil filter adapter, that's actually AFTER the oil filter, and is definitely the BEST place. That's between the oil filter and block's oil feed, so it's definitely exactly what is at the bearings (given that there might be some pressure drop based on passageway flow).
To revive and old thread: I have a 428FE in a 1973 F100, so the oil filter is a tight fit to start and I have to run a shorter filter than the usual stock unit. My question- I want to install an aftermarket mechanical gauge and retain my stock gauge. How should I hook this up and what additional parts do I need? Is there some kind of t-fitting to use, or another oil pressure port to plumb? Thanks!
No t-fitting on mine. It just comes straight up off the top of the filter pad. The gauge should come with the fitting to attach the pressure hose, all you'll need is the hardware to connect this fitting to the pad. Wish I could remember just what I used but... it's been a while.
Ah, seems I skimmed over the part about keeping the factory unit. I've never done both. I would assume that you could use a t-fitting and get a reading from both. It's a closed line so the pressure doesn't have anywhere to go so it should read correct on both gauges.