OK!! Here is my question but I will start from the beginning.. I broke the baseplate on my carb right after replacing the intake and heads,, so when I ran it with the vacuum leak it ran great,, here is the dilemna I replaced the baseplate with a new one and now getting a weird problem. when I slowly press the gas she goes but once the secondaries start to open it bogs for about 2 seconds then takes off like a bat out of hell but if i try again it would bog then backfire this happens frequently since the new baseplate and never happened before when the old plate was good my primary squirter is a 37 and so is my secondary but the front pump is a 50cc as my back one is 30cc my timing is 12 degrees with a total of 35 @2900 rpms my primary jets are maxjet size 81 and my second is 83 with anything smaller it would backfire constantly and tell me it was too lean the intake is a single plane for 2500-6500 rpm low profile design, the heads are l98 vette heads with 165cc runners dual exhaust 1 3/4" primaries into true dual straight back into glasspacks msd ignition Can you give me some pointers? By the way the main body is a proform 750 with adjustable air bleeds down leg boosters no choke this carb is a double pumper..