[arpad_m]

It's hard, because these sites use a catalog that is months behind the current version (I learned this from the people at gmpartsdirect.com).

Your best bet IMO is to contact various parts stores directly and ask for up to date info. These are typically operated by dealerships' parts departments, so they should have access to the current shop data and of course they'll know about their stock. I'd try shopchevyparts.com, trunkmonkey.com, gmpartsonline.net and others that a search may turn up.