battery question for my '67

[tavenner13]

my battery keeps dying in my '67 after sitting for a day or two. i was waiting for my girlfriend in my truck the other day and had it turned to the ACC with the radio on and it drained the whole battery down in only 15 minutes well our local cruise-in is tomorrow and my '91 is waiting on me to install a new water pump so would the battery from my '91 be ok to run in my '67?? dunno if it matters but the dodge is a 318 and my '67 has a 454