According to one of Fords websites :
For a 1969 Mercury Cougar ( all factory available engine sizes )
( .035 inch spark plug gap )
.054
The spark plug gap range for the non-Boss 302 is 0.032"-0.036".
0.054 for the 1999-2001, others not sure.
It is .004
.035
Here are the engines that came in the 1969 Plymouth roadrunner,so the spark plug gap is the same for all. I sure would like to see it.1969 Plymouth Roadrunner 6.3L 4BL HP 8cylThe Spark Plug Gap.035 (In thousandths of an inch)1969 Plymouth Roadrunner 7.0L 4BL 2 Carb 8cylThe Spark Plug Gap.035 (In thousandths of an inch)1969 Plymouth Roadrunner 7.2L 4BL 8cylThe Spark Plug Gap.035 (In thousandths of an inch)
0.054 for 1999 to 2001 V6.
Check the Vehicle Emission Control Information ( VECI ) decal located in the front of the engine compartment ( it will show what type of spark plugs to use and the spark plug gap )
.045
.035
.033 to .038
According to the Haynes guide the gap is .054 inches