3-speed to 4-speed

  1. M

    changing a 1967 3-speed to a 4-speed

    I have a 1967 Mustang that is a 3-speed and has had a 351 Windsor motor put in instead of the 289 it came with originally. When I drive it and reach third gear the engine feels like it wants 1 more gear to reach a comfortable place. This being said, I want to put in a 4-speed transmission. my...