valves question

If your car is a pre 93 5.0 then it has forged pistons in it.
I know for sure the 87-92 had forged pistons. Not sure about pre 87. Anyway your rockers will not pose a threat to your pistons....its the duration of your cam that will. As far as your pistons and the performers go i am not quite sure about the size valve the pistons will accept but i am sure that stock pistons are OK with 1.90. Friend of mine has performers on his stock bottom 5.0 with no problems. As far as the 2.02s go i am sure someone will reply here and let you know. But your pistons are forged if it is a pre 93 for sure....unless it has been rebuilt.

Thats cool. The heads on the explorer were gt-40s. They have 1.84 intake valves in them. I know for sure the 1.90 are ok. 2.02 i am not sure. Call eldebrock. They will tell you everything you need to know.

96 explorer motor is non forged but has reliefs. the performers are 1.90/1.60 valves, so you'll be fine with the e303. your problem is going to be you said you ordered the stud mount heads yet your factory rockers are pedestal mount, so you will have to buy a new set of stud mount rockers. and the studs on the performer heads are 3/8" studs.