I HAVE A 91LX 5.0.THE ONLY MODS IVE DONE SO FAR ARE 3.73,CAI,OFF ROAD X PIPE,03 COBRA R RIMS . I PLAN TO INSTALL A BEEFY CAM NEXT BUT AM WONDERING WHAT CAM TO USE AND ANY INSTALL ADVICE.I LOVE THE WAY A BIG CAM SOUNDS AND IDLES BUT AM CONCERNED ABOUT P 2 V CLEARANCE ETC.
I just asked this same question a few days ago I am very much in the same situation as you as far as mods go. Many people said I couldnt go wrong with either a b303 or e303 or a trick flow stage 1. They say you should have no problems but you should always check p-v clearance. I really didnt want to pull my heads if I didnt have to.
If you haven't swapped out the stock intake then putting a cam in it is not going to net you much gain. The stock intake is the major restriction on the 5.0 Mustang.
I would swap the stock for an explorer or cobra intake when you do the cam.