GTD gearing

I have had my GTD/40 for a little while now, and have always felt it was seriously under-geared. So this week I went out onto a quiet stretch of road and made some measurements, road speed as indicated by GPS versus engine revs, in increments of 1000rpm. The results are attached - a screen shot of an Excel sheet. Blue figures are extrapolated (my passenger started to yell blue murder when I exceeded the speed limit...). Although I have quoted estimated road speed at 6k revs, no chance that that will happen any time soon.
The spread is nice and even, but the absolute speeds are, I think, ridiculously low for a GT40. Its a mildly tuned 302, with bags or torque. The box is a Renault 369, car running on 265/50x15 wheels.
Anyone know what final drive these boxes had? Are my figures significantly low? Any other comments?


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Final drive depens on the exact type of gearbox you have: the identification number should be on a ID plate on rear cover 369 - XX
Should be 369-00 or 369-01...

The 369-01 has a final drive 9x35 (3,88)
The 369-00 is 8x33 (4,125)

original gears ratio are :

1st : 3,36
2nd : 2,06
3rd : 1,36
4th : 1,06
5th : 0,82

Being so under-geared, means you could have a 369-00...

Mike Pass

Ratio data sheet attached.


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