So I have a '91 RS with a fully rebuilt 350 I put in last summer. Its running a mild aggressive cam at about 340-350HP from the rear wheel. Been having issues with accel and speed due to the horrible and I mean horrible 2.73 gears.

I've been looking around, talking and decided to go with 3.73 gears POSI.

Good choice?
And what about the speedo gears? Would anything else need to be changed?

 

I think 3.23 (bolt) or 3.27 (9 bolt) is a better all round daily driver ratio. Especially with the power you've got.

 

It's really tough to choose the "best" gear without knowing the cam specs. 3.73:1 gears with a 700r-4 and a 350 is an awful lot of fun in town. Not too bad on the highway.

 

Lift: In: .422 Ex: .444
.050 duration
In: 204 Ex: 214

 

For what its worth, I have 3.45's, personally I think they are the BEST all around gears. I have no experience with 3.27's but had 2.77s originally and they sucked. The difference from those to now is unbelievable. Not a rocket off the line but damn quick and cruises on the highway really well. I drive my iroc a lot around town and on the highway.

 

Not sure that cam will make as much power as you think it does.

As for gears, I would stick closer to 3;42 or so. 3:73 is a bit much really for a car that sees a lot of stret use

 

I have to say 340 to 350rwhp is a bit high for that little cam but what do I know. For a daily driver I wouldn't go any deeper then a 3 42 gear.

Mark.

 

Thx for the help all. Now idk which to go for, 3.42 or what. And trust me I know the cam ain't no big thing, I wasn't ready for the rebuild process but the 305 had blown. The shop that bored the engine dyno'd my car when I came back after i finished and it was 330 HP. I've done mild work on it since then. New air flow system, intake, fuel pump and etc.

 

I do plan on putting a larger cam in if that helps. Maybe around a .48 to a .501, just trying to pass emissions first with this cam. My high idle is running HC's at 380, limit is 220 here in Delaware.

 

With that cam, go 3.42:1

 

Why 3.42, just wanting to understand thats all, so when I do upgrade I know why I'm upgrading.

 

go with the 3.42 its good for a dd

 

Even with my 5.0 I love the swap from 2.73 to 3.42 running a 700r4.(reasons being there great off the line and I can chirp the tires from 1 to 2nd and 2nd to 3rd,that's with including the Eaton Posi. and there just about right for the 700r4 and the 65mph interstate here in OD ,not to mention my speedo is right on the money with 27in. tall rear 255/65r15 tires and I use Drive as opposed to OD around town with the 3.42s.Thats a couple reasons at least for me.) Its perfect for my DD and I also installed a L.P.W.support cover.http://www.lpwracing.com/Diff_Cover_...omparison.html and here's were I bought it.= http://www.jegs.com/i/L.P.W./619/301-7.5G/10002/-1