If you are just doing a basic re-ring, you will need the standard 4.00" rings and the compression rings are 1.5mm thick with the oil ring being 4.0mm thick. I'm not sure what brand ring you want, but I know the part numbers for Sealed Power rings. The standard plain rings are E458X, and the part number for the moly rings is E458K. Hope this helps you out. Any other questions just ask.
94 GT---CHP 347, Windsor Jr. heads, 24 lb inj., Pro-M 75, Crane 2020, Explorer intake & TB, Harland Sharp RR, Paxton FPR, BBK shorties, O/R H pipe, Flowmasters, 3.73 gears, NOS 5115