ECU question

[blown motor]

Is the ECU for a 340 and a 440 the same? What's the difference in a 4 pin and a 5 pin? This one says Wells on it. Is it aftermarket?

[Chryco Psycho]

4 & 5  pin are interchangable , & they work for any engine
the 5th pin is a low voltage feed to the ECU using the second side on the double ballast resistor , all of the newer ones have the voltage drop internaly inside the ECU so you can still use a single ballast for dropping voltage tot the coil only

[chargerdon]

Not quite interchangeable.   The 5 pin was the original ECU and used a double ballast wiring system.   Then the newer 4 pin ECU fed the 5th internally.   The 4 pin systems all have a single ballast.  Not sure what years they came out.   I know that my 74 Challenger oem was a 5 pin with dual ballast resistor.   I replaced it with a 4 pin and it works great.   

You can use the 4 pin all of the time...they are pretty much all you can find new anyways.   BUT the older 5 pin ECU cannot be used on a 4 pin system as you will not have the proper wiring.  The 4 pin is the newer style and takes care of the 5th pin internally.   You cannot use a 5 pin on a system not wired for it...ie. those designed for 4 pin, because there will not be the wire for the 5.

They are inexpensive, so always carry with you on any trip a 4 pin ECU (i bought mine from autozone a mastercraft brand for $35), and a spare ballast resistor.   

[71383bee]

4 & 5  pin are interchangable , & they work for any engine
the 5th pin is a low voltage feed to the ECU using the second side on the double ballast resistor , all of the newer ones have the voltage drop internaly inside the ECU so you can still use a single ballast for dropping voltage tot the coil only

I have related question to this.

I recently pickup the Rev N Ator system with a 4 pin ECU and they supplied their 2 pin Ballast resistor for my 73 which uses the older 4 pin ballast resistor.  I know the ECU should work with the 4 pin ballast.  Will the 4 pin wiring work with the supplied 2 pin ballast?

[7212Mopar]

Yes it should work keeping the dual ballast. I used the Revnator on my 73 with the dual ballast resistor, no need to change to the single.

[1 Wild R/T]

This one says Wells on it. Is it aftermarket?

Yes, Wells is aftermarket... Lower end aftermarket.... Typically sold at Kragens type establishments...

[Chryco Psycho]

The 4 pin ECU will work with either the 2 or 4 pin ballast , the second side of the 4 pin is not used anyway

[71383bee]

The 4 pin ECU will work with either the 2 or 4 pin ballast , the second side of the 4 pin is not used anyway

Thanks CP.

So if I use the 2 pin ballast which wires do I plug into it?  I'm planning on using the current 4 pin ballast but I want to keep the 2 pin as a spare.

[7212Mopar]

I think is blue and brown.

[Chryco Psycho]

correct blue & brown to the coil

[dodj]

This one says Wells on it. Is it aftermarket?

Yes, Wells is aftermarket... Lower end aftermarket.... Typically sold at Kragens type establishments...

..throw it away....

[Chryco Psycho]

Or keep it as a spare , it might get you home