Alternator 100 or 130 AMP

meirharnoy said:

it need to be replaced.
are you able to determine which alternator (brand/model) will work for me as Plug and Play without making modification and other wiring based on the pic?

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Just go to your local auto parts store and ask for an alternator for a 1994 Mustang GT. Should be a direct swap.

You'll need to swap your pulley over.

The SN95's come with a larger 3" pulley on them that doesn't work too well on the fox body. Larger diameter slows down the alt speed. Typically, you zip the nut off with an impact, remove the pulley and swap on the fox one. Everything else is plug and play considering you already have a 3G alt installed.

Hard to see from the pic, but you may already have the larger pulley installed anyway. If it's about 3" in OD, then it is the SN95 pulley. In that case, just swap it. But if it's smaller in OD, you should use that pulley instead. The larger pulley may give you issues at idle in maintaining a charge. The smaller diameter pulley can help with this.

Since you already have the 130A alt, you don't need the cable kit. The big wire hooked to the red connector is your main power wire.

Everything I see looks like a factory 94-95 GT alt that has been installed on a fox. 1 large 4ga power wire, one larger main plug, and a small white single wire plug.

Compare pulley size with the replacement alt. It's been some years but pretty sure SN95 alt pulley is near 3". I would swap the pulleys.

Once in a while you might see a sticker on an alt identifying it as a reman, but for the most part the 94-95 alt did not have any markings on it. My alt is a part-store 94-95 alt, and doesn't say anything on it at all. Can't remember what brand it is, but it's over 20 years old and still going strong