5-Speed/rear-end gears

[Mike Bartlett]

Hello everyone, I have a question.

I am trying to decide what rear-end gears would be best for my
Cobra when using a five speed (tremec) tranny? I originally ordered my car with the standard 3:54. After some thought and input from others that may not be a very good combination esspecially with first gear being 3:27. I have heard that first gear is almost worthless, 3:54 rear and 3:27 trans. Anyway I thought I would ask to see what all of you think??

Tire size:
Front-235/60-15
Rear-295/50-15

Thanks in advance.

Mike

[Junket]

Mike you might want to check out this site http://www.smokemup.com/ plug in the numbers I belive that about .95 or 1. works for a first gear.
Ken

[Dwight]

WITH A MOTOR THAT MAKES A LOT OF TORQUE YOU SHOULD BE ABLE TO USE 3.00 +- GEARS.

[DonC]

Mike:
Take a look at http://www.368s.com/tools_rpm.phtml for a gear ratio calculator, just plug in the numbers and see which combination gives you what you're looking for..
ERA advises to keep the first gear ratio to one that will produce no more than 10 mph per 1000 rpm in first for a street machine. With the 3.27 first you can go as high as 2.88 for the final drive ratio and still be streetable. 3.31's seem to be very common with the Tremec and Richmond trannys.
DonC

[The Dreamer]

There is a 3.23 available for Jag diffs as well. I think the Tremecs w 3.27 1st have the best numbers (rpm vs speed) with this final. Cruise rpm around 2500 and redline top speed around 150 mph. I've made some assumptions to get those numbers, but most setups will be similar.