The battery was moved to the trunk to make room for the ACC servo (that we all love).
I disagree. Our '76 SL, for example has the rear battery and no ACC at all. I maintain that the battery was driven to the rear by the underhood heat issues of the early underhood catalytic converters (in 75 and 76). Early SL's have the battery under the hood in that spot. I don't know that much about SLC's except that they are fat SL's. (Well, long and tall anyhow.) I would think that underhood they would be identical to the same-year SL's. -- Jim