Well the convertor is a PTC 9.5" that flashes to 4200. Guy put it in and then drove it, but converted whole car back to stock.

I got it for $175 I think. I am way more of a 3.55 guy, but the Explorers came with a variety of ratios, and the 3.73 is pretty common and that is what is in there.

If I were buying new, I would be aiming for more of a 3k convertor and lower 3's for gears.

I would imagine though that a convertor such as mine and the gear will only help in the quarter.