im in essex closer to baltimore
here are some closer pictures of the items. The ignition control can be removed with the HEI types correct?
What does the 4 prong balast do?
The items in the firewall picture have been mostly identified, but to add to that, see the comment for each of your following additional images:
The pictured item is the temperature control valve that mounts on the cowl to sense ambient air temperature in the plenum, and opens at a specific temperature to bleed off vacuum in the ported vacuum control system or the venturi vacuum control system, in the exhaust gas recirculation (EGR) system, depending on which is equipped on the vehicle. The upper fitting has a foam filter to filter the incoming air bleed. The one in your picture has remnants of the filter on the fitting. The lower fitting connects to the specific control system.
This component can be removed if the EGR system is not being used.
The pictured item is the OSAC (Orifice Spark Advance Control) valve. OSAC was used, starting in 1973, to help control NOx (oxides of nitrogen). It is in the path from the vacuum advance on the distributor to the ported vacuum port on the carburetor.
This component can be removed if the OSAC system is not being used and replaced by a direct vacuum hose from the carburetor to the distributor.
The pictured item is the charging system voltage regulator used with the 1970 and later style regulation with the isolated field alternator using two field connections at the alternator. The regulator in the picture is an aftermarket unit.
This should be retained if using the original style charging system.
The pictured item is the ignition ballast resistor. This type ballast resistor used from 1971 through 1979 houses two resistors. The primary, or compensating, side of the dual resistor used with the ECU is the same type as the earlier point systems with an open back, ceramic housed, wire wound nominal 0.55 ohm resistor. The resistor performs a thermally adjusted coil current/voltage stabilization. The resistor also limits the current through the power transistor of the ECU, protecting it, similar to the same action with points.
The other side of the ceramic case dual ballast resistor houses an enclosed "non-thermal" auxiliary resistor which measures 4.75 - 5.75 ohms at 70-80 degrees Fahrenheit. This nominal, five ohm resistor is connected to the "fifth pin" of the ECU. Internal to the ECU, the auxiliary resistor connects to the collector lead of the driver transistor for the main power transistor and part of its biasing. It limits overall current from the 12 volt supply.
This component must be retained for the original electronic control unit (ECU) which had five active connector pins. If the "5-pin" ECU is replaced with a "4-pin" ECU, the auxiliary side of the dual resistor is no longer used. It can be left in place, or the circuit reworked for a single two terminal ballast resistor.
If replacing the Chrysler electronic ignition system with something else, the resistor can be retained if it matches the need of the replacing system, or removed/replaced as needed for that system.
The pictured item is the electronic control unit (ECU) for the Chrysler electronic ignition system. The Chrysler ECU employs timing and driver circuitry internally to switch a power transistor which “turns on and off” to switch the coil primary on and off, producing the secondary spark. The pictured component is an aftermarket ECU.
If replacing the Chrysler electronic ignition system with something else, the ECU will likely not be used in most cases and it can be removed.
