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Discussion Starter #1
Hi all!
My initial reaction, as Don Knotts would say after a swig of whiskey, is SMOOOOOOTH! The aluminum driveshaft really seems to free up the engine to let the RPM's fly...Of course the 3.73's are helping there too. But the driveshaft also makes the whole car feel more sophisticated...silky, smooth, and dare I say it...Bavarian (as in BMW).
The RPM's on the freeway at 65-70 in fifth are only 2250, and seems even quieter than stock due to the quieter driveshaft with less vibration.
 

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Discussion Starter #2
In case you were wondering...
I got the parts from FordSpeed.com...excellent prices and very quick service.
The installation was done at Tucson Differential for $260 total. This was a super price. No other shop in town wanted to touch the car unless THEY could buy the parts, and as for the two Ford dealers in town...
One service department was so busy or so inept that they never answered the phone either time I called. I hate elevator music.
The second Ford dealer said they'd be happy to do the labor for the install...FOR $500!!!
See ya, wouldn't wanna be ya!
 

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What are the advantages of 3.73 gears? I know absolutely nothing about this stuff.

Steve
 

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Discussion Starter #4
Ever ride a bike and come to a hill and wish you could shift down to another gear that's easier to spin? A better analogy...You're riding your bike and a ravenous dog runs out of a yard and wants your ankle for lunch...to start your sprint would you rather want a slow turning heavy gear or a high rpm easy gear? The stock 3.27 rear ring and pinion is fine for the all-around (especially for good-ole-American Highway cruisin'), but for a better "Bullitt" launch and city driving the 3.73's rule. People dragging their Bullitts with "sprints" as a priority are going for the 4.10's.
Also, the 100mm Denschgarger CAI on my intake really helps the engine breath and especially helps the high RPM horsepower. The 3.73 gears now help me out with more acceleration on the low end.
Some say the 3.73 gears will reduce HP by ~5HP, but my aluminum driveshaft will gain about 5hp, evening out in the wash.
 

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Dennis, explain why 3.73s would reduce HP by 5 HP. That mod is next on my list. Thanks.

John
 

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Reagarding the loss in horsepower with numerically higher gears. It doesn't cause a loss in horsepower at the flywheel. The gears have increased friction because they are spinning faster at a given speed. They also force the drivetrain to spin faster. The combination of the two accounts for the loss of horsepower at the rear wheels.

Eric
 

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The track lock is an 8.8 right? I'm looking to do a gear swap to a 3:73 next weekend myself, but have only done it on conventional open diffs not limited slips is it a lot more difficult?
 

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Buy yourself a Ford Racing catalog and you'll find lot's of cool toys for your car... including a variety of gear ratios.

When you rebuild it, don't forget the friction modifier! (Required for limited slip differentials.)
 
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