Ron Wakefield was the Engineering Editor for R&T at the time. He replaced the SL with a BMW 2800CS, then a 3.0CS.
As for the headlight flashers, I hooked them up on several US model SLs and sedans or the era. On most of the ones I did the wire was disconnected at the fuse box and taped back. I simply reconnected the wire to the fuse box.
Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex