380 hp Magnum crate dieseling problem

Well pulled the car out haven’t touched it in 6 months. Still diesels on shut dow. Holley hp 750 dbl pumper. Yes it will run with mixture screws turned in. I have set the initial timing at 10*,14*,20*. Idles 750 rpm. I had issue with pvc so temp removed. Rear throttle blade shut. It pulls about 9 on vac at idle.