Dallas--Convenience store chain 7-Eleven Inc. and Chevron Texaco Corp. will test a co-branding effort this summer at 20 7-Eleven and Chevron locations in Texas, Florida and California. Under the trial, 11 7-Eleven stores will offer Chevron-branded gasoline and nine Chevron sites will convert their convenience store format to 7-Eleven. Currently, 30 of 7-Eleven's 5,800 stores in the United States and Canada sell Chevron-branded gasoline under different arrangements. -Dallas Business Journal