by chevyart » Thu Mar 20, 2008 12:53 am
check floats first, as the other forum member suggusted. Car should be on level, and then remove metal plugs, if that is what you have, and look at the opening. gas shouls just be barely trickling out of the holes. I would do this one at a time, front first. put a little rag on the side in case the float is too high, as gas will pour out quick. and adjust float as necessary. Holley says to change one jet size at a time, in both front and rear (example 65 to a 67. you may have a meetering plate in the rear, which will prevent you from changing the size there. carbs from the factory are usually righ on in jet size right out of the factory so more than one jet size up is probably too much.. If thew float is stickink, maybe you got dirt caught in the needle and seat. that is easy to clean and reinstall and reset.If your car backfired at all you may have blown out a power valve, or it may not be the right size one. do a vacuum test, car in gear, and whatever your vacuum reads, then put in a power valve half the number ((if vacuum is 10 then put in power valves wikth the number 5.0 or 4.5. if the vacuum reads over 12 then go with a 6.5.. if you have a meetering plate in rear then you will not have a power valve in the rear. could also be a bad fuel pump. drive car up a dig hill and if it runs worse going up the hill it usually means a bad fuel pump. If the car hesitates when you are initially giving it gas it could be a bad accelerator pump, but if its hesitating after the initial gas then it is not that Pinched gas line? good luck Chevy Art