Pace Setter makes a header for the 2.2 4-cylinder motor in the 1994 and newer S-10 pickups. We have done a couple of installations in the magazine and they seem to work pretty well. Especially when you use them in conjunction with a K&N style cold air intake and one of the Flex-a-lite electric fan kits. Jet Performance (www.jetchips.com) also makes a computer chip for the 2.2. And if you're looking for a set of under-drive pulleys check out www.sportruckspecialties.com. In fact you can find all of these parts on the Sportruck Specialties web site. Hope this helps.
I don't know if they have an EO number or not. You would have to ask the guys at Pacesetter. I also heard that Al's custom headers (next door to Donahoe Racing) has them as well. He builds a lot of headers for buggies and race trucks. And I doubt his would be Carb Approved.