Rear Gear

not gonna get into the whole 3.73 vs 4.10 thing, my asbestos suit is wearing thin; but, if you are gonna get gears & a chip both, u can get chip programmed for gears, so u may not need a speedcal. i know steeda has a package out now with gears, c.a. kit, & reburn of your stock chip; i'm sure there are others as well. just my 2 pennies.

Here is a link to a gear calculator. This should help you in determining your speeds and rpms with certain gear ratios.

http://www.tchracing.com/tech/gearc...m&givenval=37&givenvaltype=MPH&selectedgear=1

Cheapest place to get a speedcal that I know of is from www.brothersperformance.com

If you have a five speed, a speedcal is all you will need. If you have an automatic, you will need a chip or ECU flash to get both the gear shifts correct and the speedometer readings correct. From what I hear, Superchip and Fordchip are about the best.

Hope this helps out and if you have any questions, feel free to ask.

Just got my 4.10's installed a couple weeks ago. Man they are awesome, I wouldnt want anything less. If you arent gettin a blower then go with the 4.10's, you wont regret it. But if your gettin blown in the future then go with the 3.73's. Just like Dark Knight said, if your a 5 speed then all you need is a speedal, if your an auto then you HAVE to get a chip. But with your mods Id get the chip for sure. Diablo or Superchip. I got the superchip programmer for my auto. Hope this helps