cranks but no spark at coil

Ok I forgot to mention I did a ballast swap (known good)from cuda to truck n vice versa. No change in truck and cuda starts runs with truck ballast. So definitely not a ballast problem.
I will chk pink wire tomorrow for voltage drop.
I tried both tapping the coil -ve wire quickly to battery -ve and holding it there. It sparks when quickly tapped. Nothing when held (obviously) BUT no spark from coil tower at all. FSM says that's the wire that should spark not the coil-ve??
Yep I changed coil wires as well. No difference.
Well, they should BOTH be sparking if You're doing it right, sparking where You tap the post & out the secondary tower thru the wire to the cap.