Completed Wire Mod: Tutorial Inside
The Best V8 Stories One Small Block at Time
1-3/4 Bi-Metal hole saw. Lowes has them and it gets the job done very well. Just did a friend's car this past weekend actually.
IIRC, I used a 1" hole saw, drilled two holes side by side keeping in mind the width of the widest plug connector and some play room for the next connector sharing the wiring from feeding the first harness through. Blend both holes together using a die grinder so that now you have a slot. Smooth rough edges, prep with paint, modify a grommet, start feeding wires.










