Hi guys,
Drove past an automatic radar "your speed is (whatever)" boxes today and it significantly disagreed with my speedo. my speedo read 70 the box read 64. 10% out !!!

I've just bought this old GQ y20 safari.
Could someone in the past have...
1/ put in the wrong instrument cluster?
2/ put in the wrong auto transmission?
3/ put in the wrong diffy?
4/ put in the wrong transfer case?
5/ put on the wrong tyres?
6/ All of the above?
From my basic understanding of the speedo I doubt if it would read high. Low perhaps, but not high.

Any comments please.

Thanks
Dave