Rear gear suggestions

[arbailey]

Looking for rear gear ratio suggestions to compliment my Thumper E7's (with GT-40 valves), Comp XE264R cam (1500-5500 rpms), and Explorer intake. The car weighs about 3300lbs w/driver and I will be using a T5-Z trans with the 2.95 1st gear (if that means anything). I currently have 3.55's but am expecting to hear 3.73, 3.90, or 4.10's.

 

[blackened88lx]

What do you use the car for?

 

[PJB]

3.73's. Thats what everybody says to get for a 5 speed.

4.10's arent really suited for a 5 speed because you need to shift too quick.

 

[EMW150]

4:10s all the way. That's what I have in our daily driver w/E-cam, Typhoon, etc. It worked great even with the engine bone stock.

 

[CarFreakGT]

I would say 3.73's for a manual unless it's a race-only car, then I would consider 4.10. Every step up in gears will get your RPM's up, especially at highway speed. If you intend to drive it on the street w/ any regularity, I would go 3.73.

 

[EMW150]

I would say 3.73's for a manual unless it's a race-only car, then I would consider 4.10. Every step up in gears will get your RPM's up, especially at highway speed. If you intend to drive it on the street w/ any regularity, I would go 3.73.

It depends on your 5th gear ratio. The Tremec T-5 in my '87 has a .68 OD and at 2500 rpms you're going 75 mph. That's definately not a race only type gear. With a 3:73 at 2500 rpms would be 79 rpms. Not much difference. It's nice to have the additional take-off power.

 

[poneypower89]

Yep, 3:73's are the way to go.

I would suggest finding some local stangers in ur area and seeing if u can get a ride in differently equipped geared cars. There is a serious difference in the pull/feel of different gears.

 

[Grn92LX]

4:10s all the way. That's what I have in our daily driver w/E-cam, Typhoon, etc. It worked great even with the engine bone stock.

Yup!

I just love it when people say 4.10's and up are for race cars My STREET car has NO problems with 4.30's. Highway speeds are fine, unless anywhere from 2300-2700 is too high for you?

 

[onefstsnake]

Well the difference between a 3.73 and 4.10 is ~ 250rpm...

 

[ferga]

And for a auto? Is ok to go with 3.73 or 3.55?

 

[arbailey]

blackened88lx
The car is not a daily driver (although it could be), it's just a car to have fun with. And now that my punk ass cousin bought a GTO, I imagine 'll be going to the track more often.

EMW150
The overdrive in the T5-Z is 0.63

Would anyone consider running a 3.90 gear?

 

[EMW150]

blackened88lx


EMW150
The overdrive in the T5-Z is 0.63

That's all the more reason to go 4:10, I didn't notice that in your post. My Tremec T-5 is .68 and like I said, 75 mph is 2500. A .63 gear would be about 78 mph at 2500 rpms.

 

[ninety15.0]

with 3.73's and 4.10's you are talking about the difference of a couple hundred rpm or a couple mph....the questions are how often do u drive the car on the street/track, what times u run, and how much power your making. IF you have any further plans for the car...i.e. FI or No2 then i would stay away from anything higher than 3.55. By the way 0.68 is the stock T-5 ratio for 5th gear....your T-5Z with the .63 will effectively lower your highway RPM approx. 200rpm. You also have the longer 2.95 first which is great in my opinion b/c with 3.73's and up...first gear is useless without sticky tires with the stock T-5 3.35 ratio. Honesltly i would throw 3.90's in there and you will benefit from the longer 1st gear ratio and shorter final drive...but you will effectively be running highway RPM consistent with 3.73's b/c of the .63 OD. By the way i cruise at 80 at 2650 rpms and consistently get 25+ mpg....so dont fear the gear.

 

[X302LX90X]

I currently got 3.73's. I got a Tremec with the .64 5th gear. I wish I got the .83. If you are racing Q-mile I guess 4.10 would be better maybe, Although my car in 4th at 6000rpm's seems to be going at best 115mph. If I bang 5th the car won't be in the powerband at all. I got about 300rwhp. I wouldn't consider changing to 4.10. If you have a more radical cam than it comes into play of staying in your powerband where 4.10's are needed. Everyone has thier own preference though.