hello, i am putting a lower temp fan unit on my wife's 1995 Z28. it goes between 6&8 cyclinders where a freeze plug is located. i have searched the world over and nobody can tell me where to get the square end tool or adaptor to remove. has anybody located one? and where? thanks

 

I believe it is 5/16" square. A piece of strong enough square bar stock and an 8 pt socket could work.

 

I took a grade 8 bolt and ground the threaded end square on a bench grinder and used a ratchet. Or, snap on sells the square socket, I think it was like 12$.