Is there any difference between two batteries that both have the same cranking amps & cold cranking amps (Die Hard vs. Wally mart, for example). A mechanic at work told me that the Die Hard will be a lot heavier (lead) than the similar Wal-mart/Autozone/... battery. I find that hard to believe. What do you think?

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1985 300CD 279k
2000 F250 powerstroke