In another thread titled "Timing", I mentioned there is a 20 degree difference in the timing from 800 to 1500 rpm's and it was pointed out that this is not normal. At 800 rpm's the timing was set at 10 deg.and when increasing the rpm's to 1500 the timing is around 30. The reverse was also true, when set at 20 deg. at 1500 rpm's, the timing is around zero at 800. I removed the distributor and did not find any broken springs and the weights seem to move smoothly. I did not take it apart any further than the plate under the points.
The distributor does not have vacuum advance. The numbers on the Bosch tag are 0231 153 009 and below these numbers is JFR4

I saw a used distributor for an early 70's B20 with vacuum retard so I am wondering if this engine should have this distributor to reduce the 20 deg. difference to normal?