www.natauto.com El Dorado calipers 1976-78 $65.95/each, $15 core. 87-91 K5 31 gal fuel injection tank part number GM-14C, about $120. Talked to the company that makes that gas tank (http://www.autobpa.com/designers/) and had them look at the plans. The baffle is to OEM specs, except that it is made out of steel, and is welded to the tank floor. Comes with the "stubby" fill neck as well already mounted. Apparently American Designers is starting to make sending units as well, but I didn't check on prices. Natauto said if the tank isn't as advertised, no freight charges to send it back, but after speaking to the manufacturer, it sounds like it would be a no hassle purchase anyways.