Thank you, so it appears that if I go with a 4 pin unit I need to change the ballast as well and then the 5th pin goes for a ride? Then I can run any of the performance 4 pin units.
My car does have a factory correct harness, most likely out of a 71 or 72 car
So if I do as follows what all can you or anyone tell me about the other performance units in addition to the 6k & 8k limits? Do they offer hotter spark etc too?
Again thank you so much
From what I read:
Note: The ECUs used from 1972 through 1979 had five pins or connections. The new performance ECU has only four pins.
3. Reconnect the five wire connecter.
4. Remove the two connectors from the ballast resistor. Note that in each of the connectors there are two terminals. On one connector, there is usually an 18 gauge dark green wire in one terminal and a 14 gauge brown wire in the other. On the second connector, there is usually a 18 gauge light blue wire in one terminal, a 16 gauge dark blue wire in the other and an 18 gauge black wire connected from one position to the other.
5. Unbolt the old ballast resistor and install the new ballast resistor in it's place.
Note: The dual ballast resistors used from 1972 through 1979 had four terminals. The new performance single resistor has only two terminals. The two extra terminals fed the fifth pin used on the early ECUs and are not required with the performance four pin ECU.
6. On the first connector of the new ballast resistor, plug the terminal containing the 14 gauge brown wire onto one terminal of the new ballast resistor. On the second connector, plug the terminal containing the 16 gauge dark blue wire onto the other terminal of the new ballast resistor. The unused terminal on each connector will be left empty. As stated in step #5, they fed the fifth pin on the ECU and are not required on the new four pin ECU.
7. Proceed to "Basic Start Up and Adjustment"