Maybe I approached this the same way you are.. For the HRR688 install, I did a few things - 1) used the jumper which FBO supplies with the ECU to bridge across the resistor, 2) added a Pertronix 40111 epoxy filled coil to mount in stock location on the intake horizontally and 3) swapped out the old mag pick up coil in the distributor - Bob at FBO stated that the 688 needs a strong signal from the pick-up coil too. By comparison to the new one, I could tell the old pick-up magnet was tired. For a few years, cold starting after sitting for a week or so would require several spins and several pumps, like the carb was leaking down. Well, I guess not.. Since installing the ECU, I pump twice and vroom. Much better behaved than with other ECUs. Not many miles yet, but so far, very good.