They have a mechanical advance curve built into them, which is easily adjustable.I would set the timing low start it up and bring the rpms up with a timing light on it to see..set the timing at 28 degrees then bring the rpms up and see how far it advance,it should be total out about say 2500-2800 you will be able to see it with the light,if you bring it up to 3000 rpms and its not moving anymore see where you are if its setting at 34 degrees at 3000 and not moving then you a 6 degree mechanical advance..if your just using it for drag racing then pull the dist. and weld it up and be done cause you dont need it advance on the drag strip..hope i helped