What is the difference between a 2 barrel and four barrel transmission. Was on Paul Herd motor book and matched the #3515845. A727B Fits 1971 E and B bodies two barrel. The next #3515846. A727B Fits 1971 four barrel E and B bodies. Trying to match a 1969 440 with the proper transmission that will fit into my 1966 Satellite that had no engine or trans. The 440 came out of a 4x4 truck, but was told the the 440 was originally out of a 69 Charger.