Steel or fiberglass? Goodmark makes what are generally regarded as the best steel cowl hoods. They're Official GM parts. You can find a retailer here: http://ecom.goodmarkindustries.com/cgi-bin/NLNETUPD?co_id=GM/&REQUEST_ID=DEALERLOOKUP
I have no personal experience with a lot of the fiberglass units, but I can tell you STAY AWAY from Unlimitied Products. I've had good luck with Harwood & I know members here have been happy with a company whose name I can't recall.
Tommy