I have a 91 Camaro RS. It has a TBI 350ci with around 350-380 hp. It has a T5 with .63 overdrive gear. At the moment, it has the stock rear end. However me and my dad are looking to change it. But, we're in father/son argument about it. He wants to the 3.08 gears in the car and just put a carrier in it. However, I want to put either 3.73s or 3.42s in. The car is driven around 3 days a week, and sees the highway maybe once a week. I feel like all that horsepower goes to waste with 3.08 gears.. Or am I crazy? What gears should I go with?

 

I'd probably do the 3.42. A 3.08 is going to be a little harder on the clutch. You will have to slip it a little more to get the car moving. A 3.42 would be easier on the clutch and still do very well on the highway with the over drive gear.

 

I have 3.73s and no overdrive. Its rough on the highway, but I wouldn't trade the back road performance for it. However this car is only driven weekends and once a month on the highway.

That being said, 3.73s with over drive really wouldn't be all that bad, and 3.42s are going to be perfectly fine. 3.42s is what stock Z28s and Trans AMs came with in the mid 90s. That is a good indication of how it drives on the street. One of my friends with a 99 Z28 swapped the 3.42s for 4.10s on his daily driver. That being said T56s have 2 overdrive gears and I am not sure what the final gear (6) ratio is.

 

What does it have now? 2.73 to 3.08 is a waste of time.

What mods does the engine have? A powercurve that completely ends at 5000rpm wouldn't warrant anything more than 3.42 absolute max.

 

The motor has vortec heads, LT4 hotcam, air gap intake, full roller motor, 454 throttle body. Bottom end is stock. I think the cam takes a crap after 5800 RPM.

 

Is there that much of a difference between 3.42s and 3.73s?

 

https://www.thirdgen.org/calculations

use the gear calculator to see what your rpm will be with each gear

 

I have 3.42s with a T-5 with the .63 5th gear. Its still very streetable. 90 MPH on the highway is only like 2300 RPM or something like that if I remember correctly. I wouldn't waste your time with 3.08s. If your going to do gears & a carrier find a Torsen Posi out of a 99-02 Trans Am/SS with gears on eBay.

 

I went with a series 2 carrier out of a 4th gen camaro. Gonna keep it 3.08. I lost he argument. And my dads right, I probably wouldn't even feel the difference...

 

Yes.

My 92 came with 3.42 stock(V6/T5). I swapped in a fairly tame 350 several years ago, which made a big difference. I then switched to 3.73 gears a few years after and it definitely made a noticeable difference. Especially from a stop and coming out of corners. My highway RPM's did go up a bit, but I rarely drive it on the highway, so it doesn't matter to me.