I can't tell if it runs any different with or without the resistor in line, I do notice it starts harder, thats why I am wondering if I need the 12v for start?

There are at least three versions and the wiring "rules" could be different for each - there are a couple of things that shouldn't change however...

(1) The Pertronix controller always needs to have a 12v+ power source to operate its internal electronics (timing computer and control). Switched "ON" with the ignition. Do not feed it with a reduced voltage source. 

(2) The base plate / point plate to which the Pertronix module is mounted needs to have a secure ground - back to the block is best.

The earliest Ignitor instructions I have to look at say that the total resistance of the coil primary circuit (may or may not include a ballast resistor) has to exceed 1.5 Ohms. Without this much resistance, the grounding transistor of the control unit will be handling too many amps and will soon die. If the coil you choose has more than 1.5 ohms primary resistance - you can run it without the ballast resistance - and you will get a hotter spark without hurting the electronics. Also in this instance (greater than 1.5 ohm coil resistance) you will be able to safely install the traditional "jumper" to the coil from the starter solenoid. This makes sure the coil gets all the volts you can give it when the starter surge pulls voltage down.

There are later versions of the Ignitor (II or III?) where Pertronix allows the use of a lower resistance coil - which would under ordinary circumstances pull way too many amps. However - the internal electronic controller employs a "current limiter" that changes the "dwell" to limit heating of the grounding transistor and coil. It will then proceed to increase the dwell as rpm increases to allow more coil amps - so long as the transistor is protected from too much heat.

I have ignitor 11 in my cars and would be interested in what you thought of the 111 after you install it. thanks.

The Ignitor II also does away with the resistor.  I recently installed the Pertronics Ignitor III in a FE 390 stock distributor and it performed very well on the dyno.  I was surprised that it did not have an air gap to set but works just fine regardless.  The digital rpm limiter that’s built into the Ignitor III is also a nice touch.  I originally purchased the Ignitor III to install in a ’57-‘58 Y distributor but it was designed for the later model distributors and not the earlier centrifugal models with the ball bearing breaker plate assembly.

Ted, thanks for the info on these, there is also a non pertronix type set up that also does not have a set air gap distance, just enough clearance is all that is required. regards bill.

On another note I guess I have to check resistance of the coil and grounding of the breaker plate. My motor was balanced from damper to pressure plate and ran as smooth as a baby's ass but then it started a slight vibration at about 400 miles after the rebuild, I thought I had a skip and went to loosen the distributor bolt and the thing jumped out of it so I know the distributor was looking for ground. (Thanks Steve) This happened twice to me. I then noticed my coil was hotter than it should be so decided to install the resistor.

I guess I have to go through all. It still runs like a firecracker but I know its not 100% anymore.