OK, I've checked out alot of threads for info on this subject and now more confused then before. I now know a 6 inch deep is a good thing but have read of conflicting sizes. Can anybody tell me if it's 9/16, 5/8, 11/16 or 13/16? Also, whats the best brand of plug to put in? Thankyou for your donations!

 

2 5/8 deep wells. One plug socket w/insert. One without or just a deep-well.

 

Motorcraft platinums, torqued to 28 ft/lb with no antiseize.