Holley 750 backfire.

Ok I was hoping to hear that. I have a set of 71 jets and 79 jets should I try the 79 jets first then go down or try the 71's? The bog is pretty bad and I can tell it's really starving for fuel. I have 25 shooters on it now bought a set of 28's same thing. I have a set of 31's I can throw on. Thanks for your help so far