Carb. popping

The accelorator pump is spraying ok.The carb is a 700 dbl pump which is from an older 340 race motor with larger than stock jets (70 jets-stock 67 jets).It also has the stock points dist.I set the timing by disconnecting the vac advance and set it at TDC (acording to the book).Is this the wrong way to set it.If I check the dwell it is at 21 when it should be at 30.Thanks