Classic/Antique Car Repair: 64 dodge dart 270, dodge dart 270, 225 slant 6

Question
Hello Brad,
    How are you. I just purchased a 1964 Dodge Dart 270 4dr with a 225 slant 6. The person I purchased it from had old gas in it and mixed about 6 gallons of new gas with the old. The car now smokes after 5 mins of running. He said it did not do this when he ran it with the old gas, but is was low so he added new. I put lead substitute and sta-bil in it and let it run, but it still smokes. I did not rock the car up and down to mix it. I cant run the car because I am smoking out my neighbors. This is a car for my son and I to work on, so we are new at this any help will be appreciated.
Thank you,
Peter

Answer
Something is real squirrely here. Just adding new gas should not make the car smoke and adding lead addative should make on difference. It sounds like a complete change of fluids like gas and engine oil would be a place to start. Then take a compression test on the motor with a compression gage. They can be purchased at most auto stores or Sears and come with instruction. Buying the gage is less expensive than having the compression tested at the local garage. Let me know how you are coming along.
Brad