Which Axle Ratio Should I Go With?

musclecar fan · #1 03-21-2010, 10:06 AM

I've got a 69 Camaro RS/SS convertible with the original 350/300 + Turbo 350 Trans with a 3.07:1 axle ratio, non-posi, 12-bolt rear. Needless to say, it is not exactly a screamer. Thinking about changing to 3.55's. What do you recommend? By the way, the car has A/C if that matters. It is 100% stock and restored, just trying to get a bit more performance out of it. This seems like the best option without hurting it's originality. Thoughts? Thanks

musclecar fan · #2 03-21-2010, 10:38 AM

Also, it has stock dual exhaust with transverse muffler, Quadrajet, stock intake, etc. The car is BONE STOCK.

southernfriedcj · #3 03-21-2010, 10:49 AM

.355's should be fine, but I'd go .373 if you take it on the highway often and .411 if you don't. I'm a fan of low gears.

**Salvatore** · #4 03-21-2010, 04:32 PM

I love low gears in a small block too. 3.55 or 3.73's are fine. 3.73's if you ever want to put a bigger tire on.

BUIZILLA · #5 03-21-2010, 04:46 PM

3.55 with 26" tires
3.73 with 28" tires

**m22mike** · #6 03-21-2010, 05:39 PM

To heck with that...4.10's....

Black Beauty does good on the I state's @ 60 I am @ 3800.
Have some fun..

Keith Tedford · #7 03-21-2010, 06:31 PM

I don't know how much performance you want, but you might want to get it dyno tuned first. If it has a factory stock slow advance curve and lean jetting, you might be surprised at how much better the car will perform. Over the years I've had cars with anything from 2.56 to 4.10 gears. For all round running I liked the 3.73s. If you aren't doing a lot of highway, the 4.10s are nice and you can always run a tall rear tire to cut the rpm a little. Calculations I found showed 4.10s should give you 3185 rpm at 60 mph with the stock F70-14 tires. My little factory tack sat on 3200. Everyone has their own preferences. If you get a chance, go for a ride in a friend's car that has gears you like and see what you think. Our Chevelle has the 4.10s and, with the couple of thousand miles we drive a year, the extra gas used really isn't a factor.

XXXGoldL34M20 · #8 03-21-2010, 06:32 PM

i will use my friends car as a sample for you as the car is almost the same as yours.
he has a 1973 Camaro Z28 RS with stock 350 motor and a 4 speed,about 300 hp stock or less.only mod is headers.
he ran 3:31 before and the car ran like a dog.
we put a 4:10 gear in a few years ago,car runs like a champ!
with that little small block you need the low gear ratio of 4:10 to get that zip out of that low HP motor and my buddys car isnt all that bad on the highway as the small block handles the higher revs just fine.

he does have the factory taller 15"x7" rims though were you have a 14"x7" so you will rev a touch higher than his 3000 rpm. i would guess about 3200 rpm when your done at 60 miles per hour.

Plowman · #9 03-21-2010, 07:04 PM

Go 373 with a 700-r, best of both worlds.

**WILMASBOYL78** · #10 03-21-2010, 07:25 PM

Keith has a good point about the performance tune-up...get the engine running the best it can, before you make other mods. The stock exhaust and intake setup will also limit your progress...headers and an aftermarket intake will make a big diference, you can keep the QJ. They are bolt on items that can always be changed back if neeeded....you might also consider an upgrade for your tranny with a mild peformance converter. I think the 3.55's are a ggod choice for the street...especially with the stock size 14" wheels and tires. You didn't mention a budget....so that obviously will impact what you decide to do. Good luck...wilma