The rear two belt grooves on an A/C are wider, 12.5mm for the compressor belts, the alternator when installed with the bracket shown will use a 9.5mm wide belt in the rear groove.
The narrow 9.5 milimeter belt if used in the wide groove of the A/C crank and fan pulleys will cause it to bottom out and not make proper contact with the tapered sides of the belt.
Look for a salvage 280S or SE front crank pulley, fan pulley and alternator bracket, from a motor with or without air conditioning, the fan belt usually 9,5 x 935mm runs in the rear grove. try to get as much of the ascociated nuts, bolts, studs, spacers and hardware as you can.
Sometimes the threaded holes in the block for the alternator bracket studs are drilled all the way to inside the crankcase, so make sure the studs used to install the bracket are not too long or they can come into contact with the crankshaft.
When I put the 127 motor back into my 230sl, I also removed the A/C compressor brackets, and moved the alternator back to position on the bottom of the block.
The 230 Kuehlmeister A/C uses a different system of belts and pulleys but the procedure to change it to non A/C would be about the same.
