Excessive ballast resistor resistance?

So I recently started hooking up a relay for my electric choke, and I'm using the blue wire from the alternator to the coil to turn on the switch. However, in my investigation as to where the actual ballast resistor IS (wiring diagrams DO NOT represent actual physical locations...), I tested the factory ballast resistor. Now, my '68 shop manual says that it should be 0.5-0.6 ohms of resistance, but I was reading 1.5-1.6 ohms.

How does this affect engine performance? Should I replace the resistor?