I love my 4.10s for my Cobra. Never topped it out, but in theory at least, the 4.10s should increase it by about 10 mph.
For a GT, 3.73s seem to be the gear ratio of choice. The GTs aren't quite as rev happy as the Cobras.
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'97 Cobra, K&N, Flowmaster, subframes, 4.10 gears, Steeda Tri-Ax shifter, Steeda G-Trac 3, Cobra R wheels w/ Goodyear F1s
My Ride