:classic: Before discarding the thoughts of seriously running the existing engine, why not run a compression test? Get a feel for what you have now. Get the SU video from Ztherapy, study, and then clean/adjust the carbs to function properly, relace the dizzy with a 79-80 280zx part, some headers,"mainly for noise on a stock engine" , get the timing set right, check for timing chain "slop"..most likely due a new one, check hard for vacumn leaks on manifold, carb shafts, brake booster lines....all these items can be used on your 280 transplant if you decide to move in that direction. 175 crank HP is easily attainable...200 possible with semi stock engine, with right setup, and proper tuning But for the same money spent on the larger blocks "280" + you will always have a more torque and HP. david