Listen to Monty. I ran all kind of combinations that always resulted in N2O backfires. Needless to say I rebuilt and even bought a couple Dominators and a new set of Dart Pro1's before I got wise and asked the expert to set up my combination. I tried running the 2* timing. My 468-9.5/1 on the dyno made 658hp on 110 @ 37*. Put the N2O and the right combination works at 22* for a 125 shot. I have been using Monty's set up for better than 200 rounds and no I will be sorry for saying this) issues.