[Big Blue24]

DDP 4's are not big by any means, they usually measure out close to 5x0135" 155* sac. While they probably run well/clean, they will hold that pump back a little in the upper rpm range. 20* timing is not ideal when trying to make maximum power at the drag strip, try at least 25* next time out, and don't be afraid to test it up to 30* when you get bigger injectors if it's still smoking heavily. Lockup is extremely important when trying to run well at the drag strip. When the converter is unlocked, you're losing anywhere from 50 to 100 HP on a 500 HP truck any time the converter is unlocked.