Answer:

The 2007 Shelby GT500 uses the Ford Motorcraft 6G series alternator. The 6G comes in a small case 110 amp version and also a large case 130 amp. The mounting for the small case and large are the same on the '07 GT500, but not all small case units have a large case match.

We can boost the output on both the small and large case 6G, but the large case is better. The larger case dissipates the extra heat from the higher output and also puts out more power at idle because of the larger diameter.

The large case is available in 140, 160, 200 & 250 amp versions. The 250 amp requires the addition of the Quicktifier External Dual or Triple Bridge Rectifier.