Which Axle Ratio Should I Go With?
 

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

Re: Which Axle Ratio Should I Go With?
 

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

Re: Which Axle Ratio Should I Go With?
 

.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.

Re: Which Axle Ratio Should I Go With?
 

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.

Re: Which Axle Ratio Should I Go With?
 

3.55 with 26" tires
3.73 with 28" tires

Re: Which Axle Ratio Should I Go With?
 

To heck with that...4.10's.... https://www.yenko.net/ubbthreads/imag...ins/3gears.gif
Black Beauty does good on the I state's @ 60 I am @ 3800.
Have some fun.. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: Which Axle Ratio Should I Go With?
 

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.

Re: Which Axle Ratio Should I Go With?
 

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. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif
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.

Re: Which Axle Ratio Should I Go With?
 

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

Re: Which Axle Ratio Should I Go With?
 

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

Re: Which Axle Ratio Should I Go With?
 

If you are anywhere near J&S Gear on Gothard in Huntington Beach, I would talk to them before deciding. I have them populate my bare '69 12-bolt housings for me, usually with Eaton guts and Tom's axles. Nothing shows, so I don't care about part numbers, I just want it done right, and that is the way they do it. I would predict they recommend 3.42 posi with that combination. Driveable on the street and fwy.

JB

Re: Which Axle Ratio Should I Go With?
 

HI go with 355 i have had 373 cars and cars with 410s always looking for 5th gear

Re: Which Axle Ratio Should I Go With?
 

I'm with you Barry.Had a mid year 'Vette with 410's.Sure could of used a 5th gear or an overdrive. https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

Re: Which Axle Ratio Should I Go With?
 

I can sure identify with Barry looking for fifth gear. I drive the five speed Jimmy all winter. Come spring and the Chevelle and I'm going for fifth. Dale always gets a chuckle when I do that. A five speed sure would be nice.

Re: Which Axle Ratio Should I Go With?
 

Here I was thining with my 3:55s with a M-21 in a convert that I had I was looking for an OD or less gear for driving it. I like driving mine though and not cranking 3k on the interstate or 4 lane. Around town or here to there ya, but a 40 miles or more one way, no thanks.

Do what a few others were saying and have it dyno tuned and have a god check out the carb and dist. I wish I would of done that looking back at it.

Re: Which Axle Ratio Should I Go With?
 

[ QUOTE ]
To heck with that...4.10's.... https://www.yenko.net/ubbthreads/imag...ins/3gears.gif
Black Beauty does good on the I state's @ 60 I am @ 3800.
Have some fun.. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

[/ QUOTE ] https://www.yenko.net/ubbthreads/images/graemlins/no.gif his motor will blow, its a mush lifter small block! https://www.yenko.net/ubbthreads/imag...lins/frown.gif

Re: Which Axle Ratio Should I Go With?
 

Thanks everyone for your feedback. It seems given the fact that I have a 350/300 + Turbo 350 Trans with a 3.07:1 axle ratio, non-posi, 12-bolt rear and 14x7 ralley wheels with T/A 235/60/14 tires, stock dual exhaust with transverse muffler, Quadrajet, stock intake, and Air Conditioning that 3.55's is the recommendation. It's not Posi now. Any reason to change to posi? Not in an Icy state, I'm in California. Not looking to race the car. Just want more Umph to it when I step on the gas pedal. It's super slow now.

If I just change the non-posi 3.07 to no-posi 3.55 gears how much should that cost me for the ring/pinion and labor? Any recommended shop or individuals that can do this for me in Los Angeles area? I'm in Van Nuys. Thanks again fellow enthusiasts.

Re: Which Axle Ratio Should I Go With?
 

Honestly Mark, I would recommend you not change the rear. Not really necessary. Car probably runs good enough for what you are doing. To go from a 3.07 non posi to a 3.55 non posi is not really worth the trouble or money. I bet you can spend that money in a better place on your car. Just my opinion. https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: Which Axle Ratio Should I Go With?
 

[ QUOTE ]
Honestly Mark, I would recommend you not change the rear. Not really necessary. Car probably runs good enough for what you are doing. To go from a 3.07 non posi to a 3.55 non posi is not really worth the trouble or money. I bet you can spend that money in a better place on your car. Just my opinion. https://www.yenko.net/ubbthreads/imag...lins/beers.gif

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Mark, Sammy is right...probably not a good idea to work the motor any harder than needed. I initially thought the gears might be a good idea...but, some simpler bolt-ons like exhaust or intake would be better choices. Get it tuned up and running good...maybe add a little "sound" to your exhaust and just enjoy it. Listen to Sammy...he is older and wiser https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

Re: Which Axle Ratio Should I Go With?
 

[ QUOTE ]
[ QUOTE ]
Honestly Mark, I would recommend you not change the rear. Not really necessary. Car probably runs good enough for what you are doing. To go from a 3.07 non posi to a 3.55 non posi is not really worth the trouble or money. I bet you can spend that money in a better place on your car. Just my opinion. https://www.yenko.net/ubbthreads/imag...lins/beers.gif

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Mark, Sammy is right...probably not a good idea to work the motor any harder than needed. I initially thought the gears might be a good idea...but, some simpler bolt-ons like exhaust or intake would be better choices. Get it tuned up and running good...maybe add a little "sound" to your exhaust and just enjoy it. Listen to Sammy...he is older and wiser https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

[/ QUOTE ] https://www.yenko.net/ubbthreads/imag...lins/smirk.gif

Re: Which Axle Ratio Should I Go With?
 

A posi would slow it down.

Re: Which Axle Ratio Should I Go With?
 

[ QUOTE ]
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[ QUOTE ]
Honestly Mark, I would recommend you not change the rear. Not really necessary. Car probably runs good enough for what you are doing. To go from a 3.07 non posi to a 3.55 non posi is not really worth the trouble or money. I bet you can spend that money in a better place on your car. Just my opinion. https://www.yenko.net/ubbthreads/imag...lins/beers.gif

[/ QUOTE ]

Mark, Sammy is right...probably not a good idea to work the motor any harder than needed. I initially thought the gears might be a good idea...but, some simpler bolt-ons like exhaust or intake would be better choices. Get it tuned up and running good...maybe add a little "sound" to your exhaust and just enjoy it. Listen to Sammy...he is older and wiser https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

[/ QUOTE ] https://www.yenko.net/ubbthreads/imag...lins/smirk.gif

[/ QUOTE ]

For a old guy he can give some great advice https://www.yenko.net/ubbthreads/imag...s/rolleyes.gif

Re: Which Axle Ratio Should I Go With?
 

My 5th generation Camaro came with 3.45s and I put 4.10s in that, but having a 6 speed with two overdrive gears is nice.

Re: Which Axle Ratio Should I Go With?
 

Another point which hasn't been mentioned is what type of driving he might be doing. Not in a street vs. strip sense, but in terms of taking it out on the freeway vs. just cruising about town.

Unlike on the East Coast where speed limits are often still 55 on even major Interstates, provided when he's driving his car isn't a parking lot on the freeways, he's going to get run off the road if he's only doing 60 in CA or AZ. So, in order to keep up with traffic, I'm guessing he'd want decent RPMs around 70-75 mph, no?

As the others said, based on your set up, I'd keep the gearing as is. jmho.

Re: Which Axle Ratio Should I Go With?
 

I've often wondered why a double OD trans is chosen when engineering a car. Seems like a 2.73-3.08 rear ratio would be best to keep drive shaft speeds down, then lowering the ratios in the transmission to get the desired gear multiplication.

My sister has a 300hp 69 Camaro. It has a 3.08 gear with a glide originally and she stepped up to 3.73. The car was a little more responsive. She never drag raced with the 3.08, but with the 3.73 the car turned a 15.01 in street form. We both drove the car and this was the best time. There really wan't much to make up in driver error.

Unhappy with that time, she then chose to install a 700r4. With nothing else changed. She then drove the car 14.2@98 (pretty sure that's what the MPH was). Not only was she happy with the results at the track, it really became more drivable. The low 1st gear in the 700r4 makes acceleration fun. I don't think the shift to 2nd is too wide.

I would strongly suggest considerign this trans. We took one form a 1992 Chevy van, simply slid the crossmember for the trans back and installed a shorter drive shaft. Still using the glide steering linkage on the column. Low gear is regular Drive. Great combination!

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My 5th generation Camaro came with 3.45s and I put 4.10s in that, but having a 6 speed with two overdrive gears is nice.

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Re: Which Axle Ratio Should I Go With?
 

I do not mean to go against the grain here. But sounds to me like you are on a budget and would like to keep your car stock in appearance. In that case I would change the gears to 3.55 or 3.73. That will give you a seat of the pants kick plus it will keep your car looking all original.
Then I would also of course have it fine tuned. Then if you are wanting a little more. Install a free flowing exhaust system.