What will 3.73s do for my '01?

Discussion in 'SVT Tech Forum' started by Ganton, May 4, 2004.

  1. I have 4.30's in my s/c'd 99. A few things to consider though:

    1. What tires will you be running? Street tires went up in smoke through 4th gear for me. Nitto's did good, but couldn't hold 1st gear with my old 4.10 gears. I now have BFG DR's and they keep the power planted in every gear...and that's with 4.30 gears.

    2. Is it a centrifical or roots blower? You said KB, so you will have much more torque at a lower RPM than I have. In this case, 3.73's might be a better choice as I mentioned in my original post.

    3. What transmission? I now have the Viper T56, so my first gear ratio in the trans is only a 2.66. That's a steeper gear by far compared to a T45 or T3650. So, my first gear matched with the 4.30's I have is like still having a 4.10 gear with my T45 ratio. But every gear after that is killer. When I'm WOT and shift to 2nd, the gear is over in about 2.5 seconds....

    Side note: if you put that KB on, you are going to HATE that IRS...hop, hop, hop.....that's why I finally put in the solid axle.
  2. As if you haven't heard it enough yet.... go 4:10's!!! I was worried about gas mileage too as most of my driving is highway, but I have not seen ANY change in MPG whatsoever. It is a completely different car with the 4:10's dude, don't hesitate.
  3. I've got an '01 Cobra and always wanted to do the gear swap to 3.73, but after hearing all of you talk, I think I am set with the 4.10's. Any brands you recommend over another? Is it true that you need to install an aluminum driveshaft or else you will feel a ton of vibration? How much did the install cost, or how much should I expect to pay for install at a regular performance shop? Did the gears throw off your speedo at all?
  4. The ONLY brand to go with is Ford Racing. Richmond makes them, but Ford Racing is the only trusted brand to go with, steer clear of all else. I am running my stock driveshaft and have ZERO vibration and ZERO gear whine...it's as quiet as a mouse. I payed $200 for the complete install and oil change at my shop. Do not pay more than $300 for install. The gears haven't thrown my speedo off, it is actually extremely accurate, but I hear over time you will EVENTUALLY need a SpeedCal, but I dont and so far everything is perfect.
  5. I thought a speedcal is a must with the install. It does throw your speed off when you're going to a different gear.
  6. 4:10's is a must for a street car.
    I wish ford would offer this from the factory.
    my gas milage dropped when i first put them on, but i bet that has alot to do with that fact i was driving it like i stole it! I can't help it. It really wakes the car up.

    my .02.
  7. :confused: Maybe once the one that comes with the gears breaks, but it hasnt been the case for me. I know my speedometer is dead on becuase cops set up those big radars that display the MPH you are going, and what it displays is dead on with my speedometer.
  8. I had 327s in my 99GT, I went to 373s and wish I has went 410s or even higher. It through my speedo off... either a chip or drive gear swap is needed. The only thing I hated about my 373s was the loud wine from the gears.... but... that is because I went with crappy gears instead of Ford...

    I have 355s now stock in my car... I think I should stay right where I am at... but I sure would love to see how she feels with 410s :)

    It is hard enough as it is to get the power to the tires... smoking them is easy... so 410s would burn them up for sure...
  9. You need a speed cal or speedometer gear. I have 4.10's and when doing 60 my speedo would read 85. Drive a mile down the road and it put 1.2 miles on the odometer.
    So let me get this straight:
    1)3.73's for a lot of highway cuising above 75, but only if you care about a minimal decrease gas mileage and aren't expecting a huge sotp effect
    2)4.30's for the track, and less highway driving and n/a
    3)4.10's best all around choice for the street
  10. anyone have 410s in their 03/04 cobras??? how do they feel? wheel hop?

  11. Correct, you must calibrate your speedo, it will be off.
  12. 4.30s are a great all-round gear and I get great gas mileage city and highway.
  13. Does someone have a chart that tells what the different top speeds are in different gears with the different gear ratios? For example:

    3.27 gears 1st 44mph 2nd 77mph 3rd 115mph ect..
    3.73 ?
    4.10 ?
    4.30 ?
    4.56 ?

  14. I just bought 4.10's for my 98, and I'm debating between buying a speedcal or just buying a 23 tooth speedo gear to correct my odometer and speedo. The 23 tooth fix is a FRPP part, so I figured I'd try it, but I've also heard that they can wear out quick. Anybody with experience in these?
  15. i went 4 10s and still could get 4 30s
  16. Check out this page, pretty nice.


  17. That's pretty cool but I don't understand how the tire width effects the speed. When I put 335 width the top speed in a given gear goes up around 5-10 over 245 width tires. :shrug:
  18. They need the size of the tire (diameter) in order to determine the number of revolutions the tire will make in a certain time period. I remember seeing some of this stuff in between naps during my college physics classes, so if you're interested you can check out this link.

  19. Here you go:


    That one allows you to compare different gearing.

  20. That ones nice too but it also takes into account the tire WIDTH that has nothing to do with the diameter. Someone please explain to me how having a wider tire with the same diameter is going to increase my speed at any given RPM? A 245/40/17 tire should run the same speed as a 315/40/17 tire shouldn't it?