I’ve seen other posts elsewhere online citing same issue… but haven’t seen a remedy. Can anyone help? Car resides in FL and many days its hot enough already without heat being constantly feed into the front seat area.
All I can add is its -7C here so pipe down, go golfing and quit bragging about your hot car. Lol
I think that year SLC (and most MBs in that period) used thermal reactors in the exhaust, which were located near the exhaust manifold in the engine compartment. That might be the source of the heat, You could try to find some kind of insulation blanket to put under the carpet to reduce the heat into the cabin.
You might have an AC vacuum problem. Broken hose, leaking diaphragm, etc.
Make sure the distributor advance is working properly and the timing is set right or advanced a couple of degrees.
Is the car equipped with some sort of seat heaters or is it coming up through the floor-boards?