Quote:
stupid speedo only goes to 85mph, any way i can tell how fast im goin?

The speedo in my 79 Firebird used to end at 85 mph or 140 kph, so I installed a geared 1.6 ratio converter so now my gauge reads to 140 mph.
Even with that, I used to bury the speedo so I made up a chart that corresponded to engine rpm as read off the tach. 5200 rpm took me to 160 mph with a 2.41 gear ratio. :P
If you have a tachometer then you should use that to give you a pretty close estimate of knowing how fast you are going after 85 mph.
MPH = (.076 x RPM)/Overall gear ratio