I tried the FiTech 600CFM system, and it did not work with my '69 Charger big-block 440 with headers... just too much heat in engine compartment for the built-in throttle body ECU to function correctly. It worked great with a cool engine, but suffered random results when engine got up to temp. no matter what I tried... just too hot ! I gave up on it and went with an Edelbrock 1411 carb. last year. Still fine tuning it, but at least it doesn't stop cold in the middle of driving because fuel pump shut off, or ECU reset, etc. like with FiTech... it was beyond frustrating ! Perhaps a small block or rat rod car with alot of airflow is the ticket to success... ( at least for me )