I'm trying to decide what gears to put in my Duster and can't make up my mind. I've got the 3.21 Sure Grip 8-1/4" axle in my Valiant now, and the plan is to swap it into the Duster when the time comes. But I've had a nice set of 3.55 gears laying around for about 3 years now and want to use them. Don't even remember where I got them.

With a moderately built /6 and a 4 speed (2.66 low, non O/D), what would you think? It'll most likely get 14 inch wheels with a 26" tall tire.

This car is to be used for drag and street racing, and some daily driving. I've been running 3.21's behind automatics for years, but I know that lots of factory Mopars with manual gearboxes came with lower gears standard.

I wonder what kind of difference in 1/4 mile times I would get between 3.21 and 3.55 gears.

With the 2.66 "close ratio" 4-speed, use the 3.55.
This gives you a 9.4 start-off which is actually a little "steep" for a Slant.
3.21 will give a 8.5 start-off ratio, basically a "clutch burner" to get the car moving.

Either gear will not be real fast on the open highway so why not give it some off the line spunk.
DD

I'm with Doc. You might see one-two tenths gain depending on how your motor and trans are set up.

Lou

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Home of Slant6-powered fun machines since 1988

Yes, I'm thinking of the 3.55's also. With 25.5" tires and 3.21's, I'm pretty much limited to 75 mph @ 3200-3300 rpm on the highway, which is borderline for the rush hours around here.

Since I want to move up to a full 26" tire for the Duster (maybe a 215/70/14 or a 215/65/15, depending on what kind of "slot" wheels I can find), I think 3.55's would be best. I figure I'm losing 3%-5% in the torque converter (stock 2000 stall) right now, and the clutch won't slip at all on the highway. So it all should come out about even.

Don't be a wussy Tim. Put some 3.91's in it and be done. I thought you were gonna build a race car???????

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Official Cookie and Mater Tormentor.

Stick in the 3.55!!!!

You don't have to worry about being at 6000rpm at 70miles with the 4spd. I would go with the 3.55s. If you put the other set, give me the 3.55, I'll make good use out of them!

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If it ain't broke, I haven't started "fixing" it yet.

Tim my man bagel is right put the 3.91 in and go for it. I put in a 3.91 when my car was a street /strip car. The car had not been driven in a while so driving down to my local strip i decided to clear things out. At 5400 rpm on the tach and 102 on the speedo the chrome windshild pieces flew off. I went back but colud not find them thats when i knew i wanted a \6 race car. Ps the car had 78000 miles on it and has gone 5000 miles down the drag strip scince then. Thanks Ron Parker








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