Owners Of 2003 & 2004 With Either 3.73, 3.90, Or 4.10 Gears...

For those here who have either an 03 or 04 GT with a 5 speed manual, I would really appreciate your help with something.

I am in the process of choosing a rear gear upgrade and am interested in discovering an actual RPM/MPH observations of owners of ONLY 03-04 GT's 5-speeds who have upgraded to either 3.73, 3.90, or 4.10 gears.

I have searched the topic and see only general RPM/MPH figures for earlier models having a different 5th gear ratio and have yet to come across the ACTUAL RPM/MPH figures for SPECIFICALLY 03-04 GTs.

So, if anyone here has an 03-04 GT, can you please tell me precisely what RPM you are turning at highway speeds? I am interested in knowing what RPM the 03-04 GTs with 5 speed manuals are turning while at 60, 65, and 70 mph with either 3.73, 3.90, or 4.10 gears.

THANK YOU!!!!!!!!

stang74 said:

02 GT 5 speed with 4.10 and 315/35/17 rear tires....at 75mph Rpm is at 2500 dead on......

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Thanks, but you have a 2002, correct? There is a specific reason as to why I said "2003 & 2004" in my title and multiple times in my post. The RPMS on a 2002 do absolutely zero for me due to a different 5th gear ratio in the tranny.

trinity_gt said:

You can make that determination yourself if you know your current rear axle ratio. Let's say it's 3.27:1. A set of 3.73:1 gears will raise engine RPM by 1.14x. So if you turn 1800RPM now at a given speed then with 3.73s you'd turn 1800*1.14 or ~2053RPM.

In general:

RPM_n = RPM_o * Gear_n/Gear_o

where RPM_n is the "new" RPM with new gear ratio Gear_n RPM_o is the RPM you turned with the old gear Gear_o. For example:

RPM_n = 1800 * 3.73/3.27 = 2053.

Go out and measure your own 60, 65 and 70MPH RPM readings and plug the numbers into the forumla to see what you'd turn with whatever gearset you're interested in.

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THANKS, trinity_gt, your post was very helpful!!