[jerryhawthorne]

I suspect that if the original cap that had a clamp to hold it to the chassis also had a cardboard sleeve over the area that was clamped? That was to isolate the cap can (negative) from the chassis which as indicated above is required. A tab off a washer under the attaching nut on the bottom of the cap would be isolated from the chassis and a fine place to pick up the isolated ground and route it to the C/T of the power transformer which as indicated is where it needs to go. Not the chassis. Now, to get the negative leads out of the restuffed cap, you will need to drill a small hole in the cap plastic base and feed a wire out to attach to the lug. Hope that make sense.
Good luck, Jerry