Here's the deal. I had to run 5K ohm resister caps with the Sparx battery eliminator. The only GOOD 5K ohm resister caps I could find are the NGK 8031, and they only accept spark plugs with a threaded nipple. THE ONLY PLUG I could find with a threaded nipple for my bike was the E3 plug. And I checked, the spark comes right out the center of the ground strap. I'd also like to add that I have a friend that has a '83 S10 and a '91 IROC Camaro, both street/strip set ups with 400hp 383 strokers. He runs nothing but E3 plugs in them and swears by them. And I feel his word is worth it's weight in gold. He's been building high performance small block Chevys with his Hot Rodding dad since he was 8 years old, and was working as an engine machinist while he was still a senior in high school. Maybe it's possible they are good for cars but not motorcyles, I don't know.
I will try to index them, see if it makes a difference. I'm in doubt of it, but hey. Here's my concern, the plugs were 100% dry with absolutely no carbon build up after running cranked at full throttle for almost a mile, and various throttle positions throughout, and it just doesn't feel like a spark issue. It runs and idles fine, just has no accelerating power. Even if the bike's not under load just revving it up, just doesn't seem as crisp as it should be.
Scottie