/ 6 Duster axle ratio? 2.76 too tall?

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Mopar92

Mopar92

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I've got a 198 auto 73 Duster that I'm putting an 8.75 for the big bolt pattern. Eventually I'll V8 swap the car. But for a while I'm just going to drive it. I have a few ratios of 8.75. I'd really like to use a 2.76 I have. I've just got 215/60/15 tires. So nothing very tall. Think this will be ok? The tag is gone from what's in it now. And I have not counted it yet. Wonder what most slant Dusters came with? Thanks.
 
I've owned a lot of /6's, but all were 225's, and most came with 2.76's. Did just fine getting the mail, or going 60 down the highway.
 
shouldn't be, if your motor is up to snuff.....
 
Actually, you can find both gears behind both motors, very common. My experiences have been 7 1/4 rear usually had the 2.76, and the 8 1/4 had the 3.21. That being said, there is really no certainty....
 
The standard-equipment rear axle ratio in '73 with automatic trans (any engine, any axle size) in was 2.76. With trailer-tow package or manual transmission, it was 3.21/3.23.

A 198/auto/2.76 '73 with your ø25.16" tires is undergeared. It's going to be sluggish and slow around town, but it probably won't be dangerously slow unless the engine is whipped and/or you're in hilly country. It'll cruise nice and quietly down the highway at 60 (a little over 2200 engine rpm) or 70 (2580 rpm) or 80 (2950 rpm).

Chrysler kind of went backwards with axle ratios. The early lightweight A-bodies with their peppy non-smog engines and small tires would've done fine with 2.76s and been much quieter and more economical than they were with their 3.23s and 3.55s. The later heavier cars with weaker desmogged engines and bigger tires and better sound insulation would've been much nicer to drive with 3.23s.

If you haven't already done so, bypass the OSAC valve, which is the widget on the passenger side of the firewall with one hose to the carb and one to the distributor. Run the hose directly from carb to distributor; that will make your acceleration a lot less mushy.
 
Mopar92 said:
I've got a 198 auto 73 Duster that I'm putting an 8.75 for the big bolt pattern. Eventually I'll V8 swap the car. But for a while I'm just going to drive it. I have a few ratios of 8.75. I'd really like to use a 2.76 I have. I've just got 215/60/15 tires. So nothing very tall. Think this will be ok? The tag is gone from what's in it now. And I have not counted it yet. Wonder what most slant Dusters came with? Thanks.
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You lost me' A-body 8.75ers were all sbp
2.76s will be a hard tug off the line,for a 198 in a 2nd gen A. .On the other hand 35mph will be about 2000 rpm in 2nd. So if she's tip-top it won't be snail-slow. I know I wouldn't run it tho,especially in a city-car.In a city car it would be 3.55s minimum. This would bring the starter gear up to 225 territory, and she will motor around as a bit bigger engine.35mph will now be closer to 2600 in second, and she will keep up in traffic much better.
So if you have something closer to 3.55, that would be the one I would recommend.
Besides those 3.55s will be perfect for a dual-purpose teener.
 
I'd go at least 323 if you can for better pick up but it is a stock slant so I don't know how much you will notice it.
 
my 73 duster with a 225/ has a 2.40 rear gear 7.25" with a 904 auto. and its not bad off the line.
 
AJ/FormS said:
You lost me' A-body 8.75ers were all sbp
2.76s will be a hard tug off the line,for a 198 in a 2nd gen A. .On the other hand 35mph will be about 2000 rpm in 2nd. So if she's tip-top it won't be snail-slow. I know I wouldn't run it tho,especially in a city-car.In a city car it would be 3.55s minimum. This would bring the starter gear up to 225 territory, and she will motor around as a bit bigger engine.35mph will now be closer to 2600 in second, and she will keep up in traffic much better.
So if you have something closer to 3.55, that would be the one I would recommend.
Besides those 3.55s will be perfect for a dual-purpose teener.
Click to expand...

I never wrote that I had an A body 8.75. It's a B body 8.75. BBP. Thanks guys, I guess I'll throw that 2.76 in it. It's fairly stout other than the annoying 1/8-1/4 throttle surge I get while cruising.
 
Mopar92 said:
I never wrote that I had an A body 8.75. It's a B body 8.75. BBP. Thanks guys, I guess I'll throw that 2.76 in it. It's fairly stout other than the annoying 1/8-1/4 throttle surge I get while cruising.
Click to expand...
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Hmmmmmmmmmm. I knew it had to be.
And If by cruising, you mean 60 plus mph, and your 198 can do that with 2.76s at 1/8 to 1/4 throttle, in that Duster,that would be akin to a miracle. I have a well-tuned, Hi-Compression, 225, that can barely do that. So your 198 would be a keeper.
But if by cruising, you mean steady-state low speed touring, that's an easy fix.
 
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