Is there a difference between the stock oem distributor and the mds?

 

The MSD HEI coil has a higher coil voltage with less primary and secondary resistance. If it has an ignition module, it is a performance one that is more accurate. The internals are made from higher grade materials and the cam gear is also stronger. It has less resistance on the posts too.

 

I bought a new cap and rotor along with some new wires because of some ignition problems. Should I have gone with the whole package and got the distibutor as well, or is it usually just the cap and rotor that needs replacing?

 

When dealing with the optispark it is best to change the entire assembly. The problems are mostly with the internal circuitry.