Lamborghini vintage Smog Tags purpose is to help with Marelli distributor maintenance and timing specs for USA smog Lamborghini.
One item of note would be static timing of 2 deg or 6 deg or whatever.
Since the ideal timing for a Lamborghini engine at 10:1 (standard
compression ratio) would be 40 degrees at about 4000 rpm, each S129
distributor would need to be set up correctly to provide this. Since
many older cars have had the smog features removed because of smog
parts no longer available, it is imperative that owner of a USA model
Lamborghini be aware of the exact timing specs of their particular car.
Certainly 20 static / 20 centrifugal is standard non smog setup,
but the S129 must be set up properly to provide only 20 degrees at the