My 97 F150 with 4.6 has over 265K miles and after discovering that the oil pressure gauge is really a idiot light, I decided to add a real oil pressure gauge. I added a 2" electrical oil pressure gauge next to the steering column. The model number of the gauge is 8264. When the engine is cold or running down the highway the gauge reads 75 lbs. The lowest reading was about 55 lbs when the engine is hot and stopped in gear. If these reading are right I may be able to get another 200K out of the engine. The second contact on the sender was not compatible with the old contact so I installed a 1/4" tee to connect both senders.

 

I don't see why that wouldn't be possible if you keep maintaining it properly and don't abuse it. There's a guy in Ohio that has over a million miles on the original 5.4 in a late 90's E-van.