Thanks for the mod information. I just installed a 143A alternator on my 1989 300CE and it works great. I can run my heater blower, defrost, headlights, stereo at idle no problem. I ended up two strands of 4ga wire 60" long with one strand 16ga as recommended. Using the stock distribution block was easy; I placed one 4ga wire on each of the two posts. The pulleys were easily switched using an impact wrench as previously mentioned.

Great mod, purchased the alternator on ebay for 115. Wire and terminals cost me $40 at a local stereo store. Took approx 3 hours of work to prepare then install, and I changed the serpentine belt as well.

Thanks again for the information!