71 Dodge Dart Swinger in England

Need to make a heatsink, might mock something up tomorrow and try. I'm also going to check the ECU wiring. My car was originally a slant six engine, so in 71 would that have had an ECU or has this been fitted along with the v8 engine? Just wondering if its been wired in correct if the loom for ECU has been added if it was originally on points