Ditto on the GM blocks. I grabbed a bunch of them on my last trip to the yard for my chevelle. I haven't found a better one for the money. They have a bakelite type body and I believe metric threads...I use 5/16 ring terminals for them. A couple pics attached....I use them for ground and power.
I'm also trying a stinger block with MIDI/ANL fuses. It is under the dash and distributes using 4 awg cable.