Actually Bob, your situation is what this thread's about. To answer your question of resistor or not, it depends on your voltage between the coil + terminal and the engine block ground at cruising RPM. Divide that voltage by the coil resistance and make sure the result is under 4. In the calculator I factored in a 15% safety factor reducing the quotient to 3.4.
At first blush I'd say you should add a resistor but without the coil input voltage we won't know what size.
The calculator can be found in the first post of
this thread.