If you're looking for free hp, the easiest thing you can do is replace the Bosch CIS injection with multiport efi. The CIS air flow meter flap robs over 10% of avail hp. Std Bosch o-ring type injectors fit the existing CIS injector ports. Use a Simple Digital Systems EM3- D (sdsefi.com) ECU and run it right off the ign coil. ODD fire V6 is NOT a problem. You add a map sensor, throttle position potentiometer, air and engine temp sensors, '81 280 zx pressure regulator, and use the existing o2 sensor for lambda closed loop. You can keep the fuel delivery/return lines, stock ignition, idle speed motor,and the intake track plumbing including the air filter housing which is not the problem with performance on this engine. You can ditch the fuel distributor, accumulator (if you want to), pressure regulator, cold start valve, frequency valve and the lambda ECU.This is a very simple upgrade to get you close to 150hp estimated. Programming is simple. I've already done it.