I have a 1950 3800 series Chev with an engine from a 1966 chev in it. The new engine is a 250 and was rebuilt years ago (12) as well as the carb. It has never un without being choked. I just bought a new rebuilt Rochester monojet and put it place and the thruck runs exactly the same. I have done all the usual thing to check for vacuum leaks and I don't believe I have any. The fuel pump pressure was 6 I believe. The vacuum is running at a steady 18 until I give it some gas and then it drops but comes right back. I have removed the fuel filter in the carb body and replaced it with an inline filter. The fuel lines are all brand new. Can anyone help me? I have been working on this truck since 93 and never driven it. Would really like to some day.
