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04 3.9 Mustang · 02-23-2005, 12:58 PM

I read from a ford ad online that the 3.9 was actually stroked not bored.
The bore for the 3.8, 3.9 and 4.2 are 3.81in. Where as the strokes are 3.39, 3.48, and 3.74in. The only differences that I know of are the stroke and a different computer. So any mods that you do that don't affect the crank or the computer will work for 99-04 V-6s. Except headers fit 01-04 or 99-00.

02-23-2005, 12:58 PM	#4 (permalink)
04 3.9 Mustang Junior Member Join Date: Feb 2005 Posts: 5	I read from a ford ad online that the 3.9 was actually stroked not bored. The bore for the 3.8, 3.9 and 4.2 are 3.81in. Where as the strokes are 3.39, 3.48, and 3.74in. The only differences that I know of are the stroke and a different computer. So any mods that you do that don't affect the crank or the computer will work for 99-04 V-6s. Except headers fit 01-04 or 99-00.