89 would be TBI (throttle body injection) like the chevy trucks had back then... doesnt appear that a carb was added from the pics shown. my 88 camaro was TBI originally, now its carb'd... theres a ton of info on TBI upgrades on the internet, i bought stuff from this site...
http://www.cfm-tech.com/GMTBIPerformanceParts.htm i bought a TB spacer, ported throttle body, and a few other things back in the day