This is correct. Mine idles at 450 RPM. Any faster and it will not up shift automatically. Ok this is how I was told how to drive mine. Tip Toe Shift is easily identified by the junction box located on the air-cleaner brace. Other under hood clues are the three wires that go to the carburetor - two to the anti-stall device at the front of the carb, and one to the kickdown switch at the rear.
If the previous owner wasn't sure, and the car does have Tip Toe Shift, chances are no one has driven this car the right way in years. Here's how to drive with Tip Toe Shift:
You don't need to use the clutch during normal driving. The clutch is only needed to put the car into "Drive" or "Reverse", or "Neutral" or "Lo".
Once you shift into drive, all you have to do is accelerate to about 15 miles per hour, then lift your foot from the gas. Wait about a second. Click! The car shifts automatically. Put your foot back on the gas and resume acceleration. No need to use the clutch.
Need to pass something? Floor the accelerator. Zoom, the car shifts down into passing gear automatically. Done passing? Release the accelerator and wait for the car to shift back into cruising gear. No need to use the clutch.
When it's time to come to a stop, just ease up on the gas and brake normally. No need to use the clutch; no need to worry about rolling backwards or stalling at the light. When it's time to go again, just hit the gas and accelerate to 15 miles per hour and lift your foot then wait for the clunk.
Hope this helps you as much as it did me.