Not sure how the converter speed is factoring here (don't think you need that much converter) but what I do know is for combo/DA I'm wanting to see 60fts more near 1.50. Cam only cars with less gear can 60 foot what your car is in worse DA. So that's something to think about. As for MPH, that's about what mine did cam only in worse DA so again we've got something going on with power on this combo....either it's not making it or its not being applied properly.