The GT's are 6 quarts, and I'm thinking the V6's are 5. If no one chimes in by the time I get home, I'll check in my Haynes manual.
I agree about the superiority of the Ford manuals. They have been invaluable over te past three years for doing work, troubleshooting and planning projects. I got mine from Helm, so they weren't cheap, but they are about 4 to five times the size of a Chiltons with a wealth of information. The one for my F-150 is two volumes, each about 3.5" thick!I like the Chilton, but nothing gives more info than the Ford Service Manuals. I recommend picking up a set of these if you plan on really doing work to your car. I found some on ebay for a good price, instead of paying the ridiculous dealer prices.