For 4th gear (1:1) pi/diff ratio x tyre circumference= kph/1000 rpm

so 80/4.625X 1.86= 24.12 kph/1000.

Are you sure about the 0.83 overdrive? Normal is 0.86 or ).75.
For 5th (0.83 Overdrive) kph= 24.12/0.83=29.06 kph/100.

Murrays speed =29.06 X 7.2=209 kph (plus tyre growth speed).
Con rod = 7.8 x 29.06 = 226 kph (plus tyre growth speed)

yeah I measure mine to be approx 190kph

Thanks Feral Im not 100% sure on the 0.83 it was listed as that ratio in the s13 service manual I have. Non europe ca18det FS5W71C 5 speed has 0.838 and the europe version has 0.821
In any language its bloody quick in a little 1200
I have the video footage on my HD now. I just need to compress it a bit to post it online as its a rather large file.
Cheers Andrew