[Automotive Engineer]

Hi folks

Does somebody know, if there are available new ring and pinion sets with 3.23 ratio for 8 3/4 with 742-case?

I've been looking from the internet, but haven't found any manufacturer.

Thanks for all information!

[dave-r]

Randy's Ring and Pinion does them but are currently out of stock.

http://www.ringpinion.com/ProductDetail ... rodID=1788

But they really are VERY common. Most racers remove them and connot sell them. So you can pick them up cheap. I was lucky to sell mine.

Most people opt for nothing taller than a 3.55:1 for performance. 3.23 is really for economy and not considered a performance part.

[Automotive Engineer]

Thanks Dave for the information!


My JS23N0 is more like a weekend cruiser than a street missile therefore I'd prefer 3.23 ratio, if it's possible to obtain one.

The 3.23 would give also better mpg that is a nice option in these days when we are having here in Finland one of the most highest prices on gasoline within EU.

Randy's seems to be out of stock, but I'll give an e-mail to them and ask about the possibility to find one.

[Eddie]

Have you tried www.brewersperformance.com or www.manciniracing.com it's possibly worth a shot. Good Luck, if I hear of anything I'll let you know. Eddie also www.differentials.com

[Automotive Engineer]

Thanks Eddie

I'll try these addresses. Hope that I would have luck with these tips. Already sent a message to Randy's Ring and Pinion, but they didn't had any more the 3.23 ratios.

I'm just wondering that why this ratio is not being produced for the aftermarkets. I know a couple of cases atleast here in Finland who has had same needs as I, but they have either installed 3.55 or found a used 3.23. In these days when people are restorating their old cars there is certainly some others who would buy a 3.23, if it would be available.

[Eddie]

I agree AE, plus with the advent of the Keisler kits and some enthusiasts willing to install an OverDrive type transmission, those 3.23's would be perfect! Good Luck, I'll ask my "contacts" if anything comes up I'll let you know.

[dave-r]

It is because there are so many good but used 3.23 sets around. Everyone wants performance instead. So they take the 3.23 sets out. It took me years to sell my used set. So a manufacturer is never going to shift them off the shelf.

If you put a hotter camshaft in the engine than stock you get better mileage with lower gears (higher rpms).

Best milage is at the rpm where the engine makes peak torque. To take advantage of that you need to gear the car to make that rpm at your normal highway speed.

[Automotive Engineer]

There are several reasons why I'm so desperately seeking the original type 3.23 gear ratio. My Chally is more like a cruiser than built for traffic light races against the smaller displacement 16V cars .

One is that I want to keep the car as close to original as possible. Here in Finland is a separate register for so called museum cars which are separately inspected and they have several benefits, no annual vehicle tax, bargain price for insurance, MOT once in two years. OK, somebody could notice that while I'm not having the original type 489-case, why to insist on the original ratio?

Because for example I don't need to recalibrate the speedometer, it gives a little better fuel consumption than the 3.55 which is more easily available. Yes, and it also gives a little better top speed...

What it comes to the connection of fuel consumption and engine torque, it's right that the Specific Fuel Consumption, which is measured by g/kWh or lb/hph, is normally close to it's lowest level at the best torque rpm. The fuel consumption litre/km or mpg, miles per gallon, is not straight related to the best torque rpm. Think only about modern gasoline engines that has the best torque at a quite high rpm-level. Engine's or a car's fuel consumption is related to many different factors. Camshaft, yes, has it's own influence, but often a "hotter" cam has bigger overlap, which leads to higher fuel cons and HC emissions by unburned fuel...

Sorry, but my meaning was not bore you all to death , but the topic of fuel cons is so close to my profession that I couldn't hold on my horses.

So back to the basics, a new 3.23 ratio is under search, but can also consider used or a whole third member with 489-case.

Just got answer from Brewer's Performance that they have one used gear set, but they have not driven with it so can't be sure about the noise. Others have not yet answered. From Randy's I got a hint to contact Doctordiff located in Montana who is specialized in Mopar rearends. Visit http://members.aol.com/doctordiff/index.html

[dave-r]

Sounds like you are on the right track to hunt one down. I knew it would not be easy to find new sets.

Because for example I don't need to recalibrate the speedometer,

5 minute job. You just swap the plastic gear at the trans end of the cable.

I understand what you are saying about mileage but as people normally don't know exactly where VE reaches peak it is easier to use peak torque as a benchmark. That is easy without measuring anything as cam duration and engine size dictate where peak torque is made.

I make peak torque with my cam at 4000-4500rpm. I used to drive at 60-70mph and get terrible fuel consumption. This was because rpms were too low.

I now drive when I can at the correct rpm (= 80-90mph) and get much better mileage. Much better indeed.

My rear gear ratio works out as about 3.35:1 (overdrive with 4.30:1 rear gears)

[dave-r]

I forgot to say. I do realise you probably have a stock or near stock camshaft and so a 3.23:1 would make perfect sense.

But over the last 25 years I have come to find the benifits of matching the gears to the cam.

[Automotive Engineer]

Yep,

The engine a stock 383 Magnum with original type carb + intake + cam + exhaust.

Swapping the speedo pinion is a easy task when you have a correct one available, but if not

[dave-r]

They are a LOT easier (and cheaper) to get than the ring and pinion set!