Per the 1977 LeMans owners manual:
It lists the R89-5 Freedom battery as the optional HD battery only.
Since it says to check and fill the battery, this kinda leaves the Freedom battery out since it was a totally sealed unit.
On a build sheet of one of my former Can Ams built on Feb 8, 1977, it lists the last 3 digits of the battery part number 240. I am still trying to locate Delco battery part numbers to match this up.
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1976 LeMans B09 Freeway Enforcer, 455/M40 Smokey
1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles
2017 Sierra SLT 1500 Z71 4X4
2019 Canyon SLT Crew 4X4
