Don't know if there's any "official" diagram of where to put them. What I do know is that the factory jacking points, at least on the 86-93 Fox, may not be the best place to support the car. They were on the unibody where the metal was thinner than on the frame rails. What do I do? On the rear, I use jackstands that have a round cutout on the top that pretty much matches the tube of the axle housing. That lets me place the stand anywhere from the center section, on outboard to the brake backing plate. Supporting it under the axle tube seems about as secure as you can get. The front is a little more of a problem. I go for the frame rails near where they turn upwards to follow the floorboards up to the firewall, obviously on the flat part, and not where it turns upwards. The problem here is that no good jackstands I have seen actually fit flush on the frame rails. I just aim to get as much jackstand under as much frame rail as I can. That's about all I can tell you.