Still shaking down my new purchase. Runs like a mother f&$@“r. But I’m trying to figure out what is going on in motor without pulling stuff apart. It has the gt40 intake but I don’t know about the heads. Sounds like a damn monster. Can definetly hear a nice cam but my I want to know about the heads. Other mustang enthusiasts want to know what it has because of the sound. Bought it from a dealer and they don’t know how to change oil let alone tell me about the motor. Is there a way to tell what heads are on your fox? I’ve looked for the typical aftermarket markings on the front the them but there is nothing there. They look aluminum. Are GT40’s aluminum or iron? Trying to tap into everyone’s expertise before I pull this thing apart. Only because I want to know
Engine 88 Fox
- Thread starter Whitehorse88
- Start date
Identifying GT40 heads
Revised 26 May 2018 to include spark plug angle pictures and text descriptions.
The GT40X are aluminum. The GT40 & GT40P heads are iron. Use a magnet and it will stick to iron, it will not stick to aluminum.
GT40 heads have 3 bars cast into the front or rear sides of the heads.
GT40P heads have 4 bars cast into the front or rear sides of the heads.
GT40 heads have angled spark plugs, flow slightly less than GT40P. Stock and aftermarket headers fit with no problems
GT40P heads have flow slightly more than GT40. The straight spark plugs mean that some aftermarket headers don't fit properly and spark plug wiring may be very close to the headers and burn easily
Revised 26 May 2018 to include spark plug angle pictures and text descriptions.
The GT40X are aluminum. The GT40 & GT40P heads are iron. Use a magnet and it will stick to iron, it will not stick to aluminum.
GT40 heads have 3 bars cast into the front or rear sides of the heads.
GT40P heads have 4 bars cast into the front or rear sides of the heads.
GT40 heads have angled spark plugs, flow slightly less than GT40P. Stock and aftermarket headers fit with no problems
GT40P heads have flow slightly more than GT40. The straight spark plugs mean that some aftermarket headers don't fit properly and spark plug wiring may be very close to the headers and burn easily
Attachments
Last edited:
