While I am not a *Ford Guy* even I admit that the 302V8 is one of the great motors, put in everything from trucks to Mustangs. The achilles heel of the 302 was a drop in oil pressure as they got elderly, around 130,000 miles or so. Such is the case of this 1990 Ford F150. You can add thicker oil but the only way to fix it is to replace the oil pump. You can buy the high volume one if you want but a standard one will bring your pressure up just fine. About 10psi at all temperatures seems to be the average. 10psi might not sound like much but it is, going from 5psi hot idle to 15psi hot idle is a bunch. You can limp your motor along, revving it up at lights but low pressure will shorten its life and that hot summer day you start it and walk away will end the motor.
Traditionally the fix involves pulling the motor to remove the pan. I am here to tell you it can be done in the the truck and in your driveway. It isn't even super hard to do. I tried to be a cheap bastard and reuse the oil pan gasket. Don't do this. Get a new silicone one. I had to go back into this truck, do everything you see here again ALL because I tried to save the cost of a new gasket. Stupid. The second video is just that process.
This has been on youtube for some time now and people have said it helped them replace their own, saving trucks and saving the mechanic's bill. Take on the project at your own risk after assessing if your skills, tools and experience are up to the task. I will be happy offer advice if you get stuck along the way but message me trough youtube, not here, I check it more.