Mixed results. A factory coil works fine for some. This guy found a Flame Thrower coil didn't work with his HEI module, making internal sparking noises: www.forabodiesonly.com/mopar/showthread.php?p=1971170753
It probably depends more on the spark plug gap you set, which can be 50-60 mil w/ HEI, if your coil can handle the higher voltage output. e-core type coils are made for that.