Rear end – the rear diff ratio is 4. something. Way to high. I need to have the ring and pinion replace. What is a good ratio for a comfortable 80 mph in 4th?
Speedometer – reads 10 mph too high and at 55 is fluctuating from 60-110 mph.
Put these two factors together, and you have the answer why your speedo reads too high. The original ratio is 2.88 which gives just over 3000 RPM at 80 MPH; not bad. I think its about right with a stock engine that has plenty of torque at low revs. The fluctuation is caused by the inner cable not running smoothly. Check for any kinks/tight bends, and grease it; better still, fit a new one; I did and its rock solid 🙂
Tachometer – reads double. This is due to a due point distributor. I am having an OEM single point distributor rebuilt with a electronic ignition to replace the points. What will need to be done to get my tach to read right?
A dual point distributor will not give double pulses unless it is way out of adjustment, but bad points or condenser/capacitor may cause erratic readings. Fix them: If you then still get a double reading, you probably have a tach fault (see old threads on this or ask again).
Front end – at 60 mph a severe shake develops that transfers into the steering wheel. I need to have the wheel balance checked but is suspect that it is the suspension. Grabbing the tire and forcing it back and forth, I do not feel any play though.
Spin the wheels and look at the tyre edge: does it run true? You may have flats on the tyre. Otherwise look at the fixing points of the upper and lower suspension joints; check/tighten bolts which may not be secure.