RogerS Posted June 28, 2007 Report Share Posted June 28, 2007 Well, Debatable. You will feel a little low end and not loose much at the top end. It will be good for all of the inbetween. I did notice a difference in the Cobra. As far as being worth it. About 400 installed and I have seen less. Value is in the end user. I, personally am going the 3:73 route. I think if you ask your tuner and state the uses you are planning he should be able to give you an inpartial answer. Then it would be up to you. Good luck and let us know which way you decide. Link to comment Share on other sites More sharing options...
ShelbyGT/SC Posted June 28, 2007 Report Share Posted June 28, 2007 You all suck! I had finally made up my mind with the 4:10's and now you have me confused again. I was thinking that if the SuperSnake had the 3:73's then maybe they were the way to go. Then I went for a ride in RIHarley's car and felt the 4:10's were good. Now you have me undecided again. I hope Swede doesn't read this. He's going to be upset with me. :P :D Link to comment Share on other sites More sharing options...
RogerS Posted June 28, 2007 Report Share Posted June 28, 2007 You all suck! I had finally made up my mind with the 4:10's and now you have me confused again. I was thinking that if the SuperSnake had the 3:73's then maybe they were the way to go. Then I went for a ride in RIHarley's car and felt the 4:10's were good. Now you have me undecided again. I hope Swede doesn't read this. He's going to be upset with me. :P :D We love you too Adam :P :P It really becomes preference. When you present your intended usage and take into account fuel delivery, turbo, s/c, naturally asp'ed, transmission gearing, suspension modifications etc. to your tuner, they should give you a very good idea of how your car should react. 4:10's may be the right gear for you. I know how my 3:73's from the 3:55's responded to my SC'ed 04 Cobra. It was perfect for my use. I traveled 195 miles round trip to upstate NY on a gumball rally and was able to manage 25+ miles per gallon. It was a T56 6-speed with the 3:73 ring and pinion change and dyno'ed at 505 to the wheels. I have found the good tuners, who specialize in tuning, will be able to assist you in your selections. However, tech's want to sell parts and install. That's what they do and how they make a living. Not knocking anyone here. But being involved in a Chevrolet dealership's service department and currently having a good tuner and tech as friends that is a fact they admit. Then you also have the possiblity of hooking up with a good tuner/tech who will have your best interest in mind. That's my story and I'm sticking to it! Link to comment Share on other sites More sharing options...
AFBLUE Posted June 28, 2007 Report Share Posted June 28, 2007 I've always been partial to the 3:90s because I've heard that 3:73s aren't much different from the 3:55s (seat of the pants), and the 4:10s are just too high of a rpm at highway speeds (for me). Link to comment Share on other sites More sharing options...
ilmor Posted June 28, 2007 Report Share Posted June 28, 2007 I've always been partial to the 3:90s because I've heard that 3:73s aren't much different from the 3:55s (seat of the pants), and the 4:10s are just too high of a rpm at highway speeds (for me). I agree...I had a 4:10 rear in my '97 M3 and just did not like the highway cruising RPM in that car. I love the Shelby low burble gurble :rolleyes: Link to comment Share on other sites More sharing options...
stump_breaker Posted June 28, 2007 Report Share Posted June 28, 2007 IMO- Normally aspirated car used mostly for city - 4.10's. You will loose top end but how many times will you go 140mph? 50/50 or more highway driving - 3.90's SC car 3.73's or 3.90's I wouldn't waste the money on a 3.55 to 3.73 swap because there wont be that much difference. I don't feel and it has been reported that 4.10's do not really decrease your mileage unless you can't keep your foot off the accelerator. At 70mph with the 18" wheels and tires your running 2500 rpm's ~. That is perfectly fine on the car but you will wind out 1st and 2nd pretty quick due to the short gear in the transmission especially when you get on it. You're going to have to lean how to use that Hurst! I think at 80 you're 3000 rpm's ~ but that is still ok on the engine but now you're going to cut into your fuel mileage. Also be aware you *might* pick up a vibration from your driveshaft since you will be increasing it's rotating speed which decreases it's critical speed. We have a two piece shaft so it should be ok but on my truck, it was very real. This is what caused the driveshaft to explode in the middle - that and the fact it was coke can thin around a cardboard tube and about 77" long! Think of it like this, at 2500 rpm's with a .62 OD gear, your driveshaft is rotating at 4050 rpm (engine rpm's / transmission gear). At 3000 engine RPM's, 4834 driveshaft rpm's. Drive shaft critical speed is nothing to ignore and is the main reason most car have speed limiters, not tire ratings and so forth. A driveshaft will explode! As I mentioned before though, these cars have a two piece shaft and are meant for speed. The SRT-10 Ram is the same truck I had but with the Viper engine. It was modified with a two piece shaft in place of the long one piece just for the purpose of high speed driving. On my Dodge I installed 4.56's and the Dodge had about the same OD ratio as the Mustang - I say the same, it was actually .08 taller. From 3.92's to 4.56's was not that noticeable until you got on it. It went from not being able to spin the tires to white smoking (while powerbraking) but during normal highway driving, you only noticed an increase of 300-400 rpm's at 70 mph. It really shone in town. City mileage went up because the engine was not working as hard to pull the truck around. What I'm going to do: We are looking at a 4.10 install but Christie might come into a little money which means we will get the SC sooner then planned. If that is the case, I'm going 3.90's. If I can't get 3.90's I'm going to stay with current gearing. After all an additional 200 HP from a Whipple or Kenne Bell will make up for the gearing! Based on previous experience, moving the mechanical advantage to the rear of the car is so worth it but it also depends on what you use the car for. Link to comment Share on other sites More sharing options...
ShelbyPilot Posted June 29, 2007 Report Share Posted June 29, 2007 ....Thanks all. After thinking about it and getting a healthy 50 new ponys from a tune I think I am going to hold off on the gear. I don't think I want to go as big as the 4.10 because of how I intend to use the car and I don't think I want to invest the money for a short step up to the 3.73. Maybe after I get used to the power I have and need a new sensation, I'll look for a 3.90. Thanks again for all the input. Link to comment Share on other sites More sharing options...
stump_breaker Posted June 29, 2007 Report Share Posted June 29, 2007 ....Thanks all. After thinking about it and getting a healthy 50 new ponys from a tune.... Without going back and reading everything, what tune is that? Is that only for the SC cars? Link to comment Share on other sites More sharing options...
ShelbyPilot Posted June 29, 2007 Report Share Posted June 29, 2007 ....It was a custom tune done a dyno yesterday. Link to comment Share on other sites More sharing options...
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