I have no clock, but do have a Retro Radio, either way I have a 67 Dodge A100 and the battery never drains, so I getter get a good tester (no harbor freight units) and see if I can track it down. Once I do I am certain I may still need replacement battery. Question is, how many cold cranking amps do I need for my 2.8L ? is 600 CCA's enough?