[cycleguy55]

Originally Posted by Bobcat

Since I`m not tracking the car much now , trying to make it more streetable. Changed the shock valving and all coil springs .

Decided to go to a VA recurved Duraspark in place of the MSD mechanical advance unit . Can`t complain about the MSD unit .... 10 years and only replaced one cap ( almost 10,000 miles ) .

The MSD doesn`t require a resistor ..... does anyone know if the Duraspark unit does ? I`ve got one , but don`t want to put it in the circuit if it`s not needed.

thanks

It depends...

IF the coil has .08 primary ohms or less, then it will need a ballast resistor for continuous running; for drag racing, short term usage, usually not.
Now if the coil has .14 primary ohms or more then it would not need a ballast resistor at any time.
Does this Duraspark wiring need the ballast resistor?

If the original Duraspark II coil is to be used, it needs to be supplied with about 9 VDC, not full battery current. That means a ballast resistor or resistor wire needs to be used. Optionally, a different coil that can use 12 VDC can be substituted for the DS II coil. Many aftermarket performance oriented coils work fine with a Duraspark setup. The Duraspark II module (blue strain relief) needs full battery voltage.
https://www.crankshaftcoalition.com/...spark_ignition

Break out the VOM.