From the 2013 GT500 Owners Manual Supplement v2 Page 25
Wheel Lug Nut Torque Specifications WARNING:
When a wheel is installed, always remove any corrosion, dirt or foreign materials present on the mounting surfaces of the wheel or the surface of the wheel hub, brake drum or brake disc that contacts the wheel. Make sure that any fasteners that attach the rotor to the hub are secured so they do not interfere with the mounting surfaces of the wheel. Installing wheels without correct metal-to-metal contact at the wheel mounting surfaces can cause the wheel nuts to loosen and the wheel to come off while the vehicle is in motion, resulting in loss of control
Retighten the lug nuts to the specified torque at 500 miles (800 km) after any wheel disturbance (tire rotation, changing a flat tire, wheel removal, etc.).
Wheel lug nut torque*
100 ft-lb 135 NM
Bolt size 1/2]x 20
Torque specifications are for nut and bolt threads free of dirt and rust. Use only Ford recommended replacement fasteners
I know some of the above posts are seen as fun and games to knowledgeable people, but you have to consider the fact that there are less knowledgeable people reading them that do not realize that they are for amusement purposes only. There are people that will take some of this "advice" and will use it and pass it along as gospel. Usually ending with bad results.
So please keep this mind when posting on technical subjects.
Thanks guys..I did not have quick access to my manual at the time. I figured someone would chime in quick. 100pounds. Not even sure if that would be in the manual or not. Thanks again
****Use only Ford recommended replacement fasteners****
A wheel nut is a wheel nut, ALA it has the proper thread pitch, seat type and depth for your wheels it's good to go.
I just picked up 20 wheel nuts 1/2"-20 with a 3/4" hex head (60' seat taper) for a little more room to fit my RPF1 wheels that I'm using to drag race. I'm doing a lapping day later this year and will plan on using all 20 wheel nuts on my PP wheels. They'll give me a little more room around the bolt holes so I don't risk scratching the finish with the constant wheel torquing that I'll do after each session.
I think the proper procedure is known as "farmer tight". My Dad used this method frequently. You tighten until it snaps then back up 1/2 a turn.
Now that we have Ford's recommended tq spec, I took a driving class and they checked everyones wheel lug tq at 90 ft lbs. Probably a middle of the road safe spec.