This Ducellier distributor, without a vacuum capsule, uses the original curve of the Ducellier 4137A distributor, except for the absence of a socket for a mechanical rev counter.
Advance curve in "Distributor revs":2° at 350 rpm / 5° at 800 rpm / 11° at 1400 rpm
To measure engine revs on the vehicle,multiply the revs and degrees by x2.
The curve of this distributor is adapted to SP98 gasoline.