Hi i want to get some new gears this week. I have heard everyone that is everyone say to get 410's but i will be putting on a supercharger this winter so i dont know weither to go with the 390's or 373's.. and also how much we talking for an install thanks

 

I would put 3:73's on just to be safe. Install will probably be around $300ish. If you don't have one already, you might want to get a chip/tuner to adjust your speedo with the new gears also you can use it for your future plans to get the most out of them. I have a xcal im selling if your interested. Just PM if you are.

 

3.73's for sure..

 

Ill also recommend 3.73s with a power adder.

 

The gears I'd recommend depend to some extent on the blower you'll be installing and the car its going on. A serious forged shortblock and high horsepower setup might benefit fromthe 3.55 set (used by lots of cobra and turbo guys with serious power). In general terms, the 3.73's would be correct for most average sc installs. Check out the web site of the manufacturer of the blower to see what recommendations they have. Things like gears are usually listed for the various kits, as are other items that may or may not be included in the kit but recommended for your car.

tripleblack

 

If you are going Vortech or any other centrifugal supercharger, go with the 3.73s. If you are going KB, either leave the stock gears or go 3.55, which would be pointless anyways so just leave em stock if KB and just save the money for the blower.

 

There are a number of guys with 3.90s and even 4.10s on a supercharged car with a 5 Speed Tremec 3650(late 2001+ GT, Mach1, 01 cobra, 05 GT...). 4.10s is pretty much the limit however as going any steeper would require a shift into 5th to finish the quarter mile hard. 3.90s would give you some breathing room if your anywhere over 400rwhp and maximize your quarter time better than 3.73s.
3.55s came stock in mach1s and 03/04 cobras but they can almost always benefit from 3.73s or 3.90s depending on the power output.

If you're getting a 1.7L kenne bell, I would still not get less than 3.73. Unless your forged and running an extremely small pulley in their bigger (2.2?) more blower, you're not gonna outgrow the 3.73s

 

why would you want taller gears with more power? just way too much torque and even more torque multiplication from shorter gears would just blow the rear end out or what?