Hi,
nice picture
But, you should check or change your thermostat, the temperature is a bit low, the needle should be above 80°C.
What tyre size do you drive? IMHO the engine is reving a bit high for 145mph... if bone stock means, you have a 2.87 diff.
And: "economy" shows , that you are off the gas?
This ist my 300TE with the (european) 3,27 diff, front intake scoop cut
but still with complete cats at a legal run on the Autobahn last summer:
bis denn,
Christian
1989 300TE