Electronic Ignition Box
i think im wrong already but isn't the 5th pin something to do with a/c?? it add more timing to help idle with the compressor loading the motor down??
No, the 5th pin is simply an earlier design
You can NOT tell all 4 pin modules by counting pins. Some 4 pin modules physically have 5 pins
If you have a 5 pin ECU, you MUST use a 4 prong ballast
If you have a 4 pin ECU, you CAN use either 2 or 4 pin ballast
I'm not aware of any documented proof that any Mopar ECUs actually had "rev limiting" built in. I suspect it is more "bad design" of some replacement boxes.
The first Mopar system I ran was bought off a guy RIGHT after it came out "factory" about 73, when I swapped the 340 into my 70RR body. I ran that system for a long time, and don't remember replacing anything, MAYBE a ballast.
Since that box had a long history of dependability, I swapped another spare I had into the car when I sold it, and put the 340 with a mild solid cam into my Landruiser. That engine --in mudholes and on sandhills--routinely saw 7K or more. Stock, black, 5 pin, early, Mopar box. No rev limiting.
Having said all that, the "pile" of Mopar boxes I have are all cheap replacements. I decided to try an HEI conversion module triggered by a stock Mopar breakerless dist because of cost and simplicity.
