I remember talking to my neighbor years ago who was a GM instructor at the tech school in STL and he was a big proponent of Delco batteries. As you look at a Delco battery and it is not "rated" the same as a competetive battery, he noted that it is in how it is tested. Sure, the comp claim a 1000amps, and the similar size AC Delco is 750amps. But that is 750amps at the cold temp, not 1000 amps at a warm temp. Often at the low temp the AC Delco is rated at the so called bigger battery doesn't cut the mustard. My 94 Cadillac has an AC Delco in it now and it is going to stay that way. My 91 Bonneville went 7 years on the OEM Delco battery. And the only problem was it was losing its reserve, but it still would start the car on a cold day, but leave the radio on for 30 min and it was dead.