So I recently got a 1966 Thunderbird with the 390 FE engine, and have access to an old 1970 Cobra Jet 428 FE engine and rear end from a Mustang. I want to boost my horsepower numbers up at the wheels a bit to match a buddy's 1970 Imapla, but don't want to do an engine or transmission swap. What parts can I swap out to bring up the numbers without pulling the engine?