I've wanted to pass this on.
I've been on a hunt for electrical parts and have been frustrated about the availability and selection in my local shops (small town). I hit pay dirt this morning and finally found a source of #8 wire and relays.
This is a Car Quest parts store but it's really an old mom and pop shop of the old time kind. Lots of old dudes behind the counter and you pull up a stool and talk to someone who knows stuff. The back part behind the counter is huge compared to the front of the store. I was referred there by the local tractor parts store, and it was off the main street amongst the machine shops and repair garages.
The other parts stores, Kragen, Auto Zone, Pep Boys, even Napa, have a limited and same selection with no wires larger than #10 and no way to get a relay except as a OEM replacement. Well, unless you count generic batt wires.
I found Carquest #S-654 socket/pigtail with a matching 12v 30 amp 5 pin relay with stout 14awg wires (they look like #10's) rated 600 volts and 105C. They also had #8, #6, #4, wire, black only (but I'm not complaining). Lastly they had the ring crimp connectors for #6 wire out front.
I about fell over.
Old dudes rule, they just do. He knew just what I wanted, a relay with a socket to plug it into. The tractor place called him ahead and he had it waiting for me. They now have a customer for life.
Secondly, I recently found a good HEI wire set for under 40 bucks. This was at Kragen (could have been anyone). It is the U build type MSD set that is their non premium line (still says MSD on the wires). #55511 SF 8 CYL Multi-angle sock/hei. Street Fire an MSD brand USA made. 8mm spiral wound w/silicone sleeve. The plug ends are already molded on, nice.
BTW - The relays are for lights and accessory additions that I do not want to run through the poor old waggy switches. The #8 wire is for the charging circuit I recently rewired. I'm using #10 between the alt and starter relay and #8 would be so much better with my new circuit breaker (pulled the fusible link).