I have a friend running one in a '99 SS w/415ci solid roller LS1. He likes it but the reserve isn't very good. You only get a few chances to start it and you definately don't want to use it to crank the engine through to adjust your solid rollers. With it not being your primary battey you may not have these issues but I'd be curious as to your reasons for wanting/needing a second battery. If it's for stereo equipment or along the same line you'd be better off with the optima due to their reserve. The red top in group 75/25 is 25a for 90 minutes. The Dynabat is 16a. They both have a specific use and are good for that use but we need more info on your intended use.