I have a1994 chevy S-10 truck and want to put a 350cid engine in it.
What year engine should I be looking for?

If you go with an older 350 with throttle body injection, you can use the ECM that was matched up with that motor. A newer 350 (5.7 ltr) will also need the correct ecm but there may be sensors to change or eliminate . I would shoot for a pre 1984 350 with the simple ecm (OBD1) about the only thing that ECM does is watch the 1 O2 sensor and fuel pressure and control . Or just eliminate all of that crap and use an old fashioned 350 with a Holley or Rochester carb and an MSD ignition system.