Any aftermarket stall convertor will launch a car at a higher RPM. The well built ones will not really be noticeable after that with excessive slippage. It's impossible to gage improvement with no A-B comparison, so using a stock convertor
first is a good way to tell if a vert helps or hurts. If your 60 ft time improves dramatically and you don't lose any measureable MPH over the stocker at the track, it's a good vert. If you gain a few tenths in the 60 but lose 4-5 MPH in the traps,
it's not. The worst scenerio is a loose vert that frys the tires on the launch and than slips excessively in high gear, meaning you just paid $$$ and did a lot of work to go slower than you would have went with a stocker.
