OK, so you have 3.73s already.
That's good.

If you've got 3.73, then IMHO moving to 4.10s is a lot of expense for minimal gain, it's only a 10% difference. If you had 3.55 or 3.31 (like I had) then it's a good move to 4.10s... Or if you had really large tires, you could step up to 4.56. But I think you are good with what you've got, assuming you have tires that are somewhere close to the factory-original size.

 

Wheels and tires are factory (17"). I am thinking of going to Ford 18" wheels with close to factory size tires. I believe the gears that I have aren't the problem, it's the fact that my 5.4L engine only puts down about 200 HP to the rear wheels, if that. So, in this case I think more power would be the all around solution.

 

I have a '04 too and am going through the same things in my mind. I'm raising my truck and putting bigger tires so I will be looking for more power. I would love to do the SC, but damn that is a lot of money. I was hoping to find information on adapting the supercharger from a Lightning to our motor but I'm not having any luck.

 

http://www.madenterprise.com/scparts.htm
I personally know several guys who have added a Lightning blower to their trucks using the components listed.

 

Man, can't thank you enough, I've been searching everywhere for info like this....

 

Troyer Performance.com


Been tuning fords for awhile now.

DEFINAETLY go to them for your truck.

 

I've got a 351 in my F-150 that I run at 75 mph with 4.10 gears and no overdrive just 3 speed auto c6. I have gone so far to cruise 85 and past 4000 rpm. I love low gears but I am planning to run a 5 speed overdrive in my other truck because I think I need a good highway gear.