HEI cap and rotor

[D-Rat]

Are these standard pieces, or did they change a lot over the years? The PO on my truck converted it to HEI, and I want to get a new cap and rotor, but am not sure what to ask for at the parts store.

Also, if you pull a plug wire at the dist with the truck running and the visible spark from the cap is intermittent only, does that mean I have an issue, or does it not necessarily produce a visible spark with every rotation with the wire off?

As stated in several other threads, I'm trying to track down a power loss / backfiring issue and am going through the whole ignition. Plugs were done yesterday...I'll do wires today, and a cap and rotor if there's no difference there.

Timing is about 10 degrees at 850rpm. Should that be backed off a bit...say to 6 degrees?