3.55 vs 3.73

Guest · Post by **Guest** » Sun Jun 11, 2006 11:19 am

I posted a question about this before, but didn't get any good advice. I want to hear from people with 3.55 gears and 3.73 gears in their cobras. Is 3.73 to steep for street? Do you feel you lose 1st gear? which gear is better for a weekend driver? Is there a big difference between the two? Do I need to purshase a installion kit for the shop to put in the gear? Any advice is appericated.

QWKSNKE · Post by **QWKSNKE** » Sun Jun 11, 2006 11:21 am

3.73's are very streetable

Post by **BADBOY** » Fri Jun 23, 2006 12:55 pm

You will need more than just the gears to do a correct install, but a good shop will have all they need to do it.

373's are a bit much and 1st gear will be close to useless.

Guest · Post by **Guest** » Fri Jun 23, 2006 3:59 pm

Yeah that would suck to lose first gear. I am leaning towards the 3:55's. But I'm just worried once I get the 3:55's, that I will be wishing I would of gotten the 3:73's?!

Post by **BADBOY** » Fri Jun 23, 2006 4:04 pm

Its 2 or 3 sizes up from the stock 3.08 gears to the 3.55 gears.

You will notice a difference.

QWKSNKE · Post by **QWKSNKE** » Sun Jun 25, 2006 9:57 am

BADBOYSPACK wrote:You will need more than just the gears to do a correct install, but a good shop will have all they need to do it.

373's are a bit much and 1st gear will be close to useless.

I have had both and saw no noticeable differences between 3.55's & 3.73's in 1st gear.

Post by **BADBOY** » Mon Jun 26, 2006 6:04 pm

If fuel mileage wasnt a problem it wasnt driven as a daily driver then I would uses 3:73's

phorty · Post by **phorty** » Tue Jun 27, 2006 11:19 am

I would definately go with 3.73's. 3.55's are perfect for regular 5.0's. My 89 had them and they were great on the highway. With a slightly higher RPM motor in the Cobra, 3.73's are a match made in heaven. I have 4.10's now that the previous owner put in and they are a bit much. But even those aren't too bad on the highway. Get 3.73's, have the traction loc rebuilt at the same time if it needs it, and you'll have a new car. If you get 3.55's, you'll regret that little extra that you're missing.

Guest · Post by **Guest** » Tue Jun 27, 2006 3:01 pm

I'm sold on 3.73"s!! Thanks for all the info guys.

Big B · Post by **Big B** » Sun Jul 02, 2006 6:10 pm

3.73 are the way to go. You will notice a very big difference.

phorty · Post by **phorty** » Mon Jul 03, 2006 8:46 am

I just thought of something that may be an issue for you. When doing a gear swap, you also need to install a new speedometer gear in the trans to correct the speedo. It's very easy to do. However, and correct me if I'm wrong, on 90-93 Mustangs transmissions, the speedo CANNOT be corrected beyond a 3.55 with simply a speedo gear swap. It is a more involved process to correct the speedo when using 3.73's, 4.10's, etc. The aftermarket may have fixed this problem by now, but I'm not sure. Just something to consider...

Post by **BADBOY** » Mon Jul 03, 2006 9:04 am

I thought people had posted what gear color to use on the other site.

Big B · Post by **Big B** » Mon Jul 03, 2006 4:31 pm

the only way to fix it after the 3.55 is to change the internal trans gear. you must split the rear cover off and slide it out. It is a pain to do. If you use the 23 tooth gear for the cable with 3.73gears, the speedo won't be off by that much.