The Elusive 1/4" Drive 5/8" 12pt socket - FOUND!

[bentwrench54]

The 1/4 is what will prevent it from working.
I took a 1/2" drive 5/8" shallow socket and added 4 wrench flats which worked good on an angle plug SBC w/ headers application; just turn it with a 3/4 or 19mm wrench.

i remember SLP used to sell a modified spark plug socket for that very purpose. ~$20 from Summit racing if i remember right.