triple trouble carbs

I been running into a problem with my road runner. I have the 440/6 pack set up on it an i cant get the car to idle right at all. Its a new motor but the problem has been carried over from previous engine as the same fuel delivery has been used on the new engine,Although i cant even drive it with the new engine. I have rebuilt all the carbs In fact the center carb has been off a few times in the last couple days. I have Narrowed it down to a vacum leak/warped base Plt. I have found on the outboard carbs from the throttle rods I can spray with carb clean an idle clears up some, Or holding my hand over the rear of the center carb helps too. The motor revs fine but if held at a high RPM it gets very choppy and wants to come down. Im about 1.5 turns out on air idle screws ive gone farther with them but not getting any reaction at all unless completly closed. I have removed the throttle rods and they are very lose with lots of play.... On a very limited budget can this problem be fixed without carb replacment ? Cant seem to find new base plates anywhere. Is about a 10.5 comp motor, performerRpm allm heads, light bumpty cam and 34 degrees total timing. But like i said THe other engine ran the same.