mag is grounded directly to case/head.
shorter path.
I had a friend (Al Diem) make up some special ignitions I used - extremely short plug to coil - then, a remote CD setup (In shrink tubing) to the coil. so the total loop of HV was about 4". (coil to plug to head to coil) I used a small plug in a ST2300 on alky n a splash of nitro . better than any of the so called perfect Pattern engines I see. smooth as glass and 9000 on 18x8 APC
still------ too expensive to feed.