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Duster2022!

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I have a 72 dodge demon that I’m running a 440 big block. Motor was dynode at about 537 horse at 6000 RPMs. I am trying to figure out what gears I should use in my 8 3/4 rear end. This is strictly just going to be a street car. Not sure if I’m going to ever drive it long distances on the highway but maybe occasionally I will. I’m looking some advice on what would be a good rear end gear I want some thing that is quick from white to light so that I don’t get eaten up by all these imports, but I also want something that I can possibly drive to car cruise ins that are out a little bit of a distance.
 
Your big problem will be hooking .
I put 3:23 behind similar power, cuz it'd smoke the 12 inch M/T forever with anything lower .
That was a build !
 
I'd go 3:91 or 3:55s, I've got 4:10s in my duster right now, about 400 horse, with 295 50 15 rear I can still cruise at 55 on the interstate...
 
So you’re saying that you are not that happy with 4:10 gears? I am only 100 hp more so you don’t think 4:10 would be good for me?
 
IMHO do the 3.23s. That way you can drive it anywhere you please. With that much horsepower and torque you sure don't need anything lower (numerically higher) to plant you in the seat. Since you aren't racing it seriously why beat on your combo more than you need to have fun. I've used 3.91s, 3.73s and 3.55s, but always keep coming back to 3.23s for a street car.
 
Seriously, you've got what- a 3200# car? 537 horse? Unless you're racing every weekend, you won't "need" 4.10s or 4.56s to have fun on the street (ratios aren't HP dependent; it's more a function of how much torque you make at your average operating RPM. Think about it- Top Fuelers run 2.90 gears...) and keep it livable. Believe me, you don't want to deal with driving that thing at your rated 6K all day long.
 
Professor Fate said:
Seriously, you've got what- a 3200# car? 537 horse? Unless you're racing every weekend, you won't "need" 4.10s or 4.56s to have fun on the street (ratios aren't HP dependent; it's more a function of how much torque you make at your average operating RPM. Think about it- Top Fuelers run 2.90 gears...) and keep it livable. Believe me, you don't want to deal with driving that thing at your rated 6K all day long.
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So what get are you suggesting?
 
Duster2022! said:
So what get are you suggesting?
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S'cuse me- I hit "Post" before I was done...
I was going to suggest 3.23s or 3.55s. Maybe 3.73s if you REALLY don't intend to do any highway driving. You didn't mention your transmission, so this is assuming a non-overdrive trans with a 1:1 final drive. If you're running some type of overdrive, feel free to dive into deeper gears.
 
Professor Fate said:
S'cuse me- I hit "Post" before I was done...
I was going to suggest 3.23s or 3.55s. Maybe 3.73s if you REALLY don't intend to do any highway driving. You didn't mention your transmission, so this is assuming a non-overdrive trans with a 1:1 final drive. If you're running some type of overdrive, feel free to dive into deeper gears.
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727 street strip from Monster Transmission
 
Duster2022! said:
So you’re saying that you are not that happy with 4:10 gears? I am only 100 hp more so you don’t think 4:10 would be good for me?
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Oh Absolutely Not Brother! Heck if you went with a 275, it's got a narrower contact patch but it's an inch or so taller than the 295 50 so that it reduce your cruising RPMs even more and with the power you have that should keep your RPMs down even lower so it may be a great choice for you!
 
If it were a drag/street car, I would suggest 3.91 or 4.10.
For what you say you want to do?.... 3.55s . For a 400hp motor, I think a good compromise gear would be 3.23, and they could work for you, as could 3.73. But i think you'd be happy with 3.55.
(This coming from a guy with 3.91s behind a 500hp 440, 4.57s behind a 500hp small block, 4.10s in a stock rr, and 3.50s in a light car with 15x33s and a 540.)
Two of those cars have had LOTS more gear.....(4.56 in the 440 car, 5.14s in the small block) and ran just as hard with less gear.
And you can always adjust things with tire height too.
 
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if you cruise here on iterstate at 55 your going 25 mph less than traffic
 
33IMP said:
If it were a drag/street car, I would suggest 3.91 or 4.10.
For what you say you want to do?.... 3.55s . For a 400hp motor, I think a good compromise gear would be 3.23, and they could work for you, as could 3.73. But i think you'd be happy with 3.55.
(This coming from a guy with 3.91s behind a 500hp 440, 4.57s behind a 500hp small block, 4.10s in a stock rr, and 3.50s in a light car with 15x33s and a 540.)
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I have a 537ush horse 440 with a street/strip 727 tranny, running 28 inch tire with street slick. You still think 355s? I was looking at 373 gears at first
 
I don't think it will run ANY harder with 3.73s than 3.55, and rpm will be a little less under cruise conditions.
If you want more than 3.55, I'd go to 3.91s. They work good in my car, but it's 90%strip car.
I guarantee you won't want, or need, more than 3.91s.
 
tedsweet said:
if you cruise here on iterstate at 55 your going 25 mph less than traffic
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Agree but most of our interstates here are three to four lanes wide, unfortunately because the rocket scientists that decide these things don't think about future growth in the area so by the time 10 years later they build the piece of **** they've talked about it's already about outdated
 
Duster2022! said:
will 355s get off the line goid? Stop light to stop light?
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I ran 355 in my 68 Coronet, w/ a Built 383 4 Speed, had 323s first, ran some 456s foe a week (that was way too much, but fun as heck, till ya hit 295 or whatever) the 355s were the hot ticket for that combo you could be cruising in fourth slam it down in the third flat footed and all the cars that we're doing around 70 next to ya, disappeared, and you still hitting in 4th gear next! Pulled out of a place one day, and got stopped by a State Trooper( he said I was doing fine till I hit second gear I was doing over 80 mph)... I had two of my buddies with me (one of them was drunker than hell, his younger brother was passed out it) could have got ugly! They actually wanted me to walk the line in a ditch, I politely refused,and he told me to go in about my business and to keep it slow...
I did, Slow all the way home!
 
I'd go no bigger than 3.55's. My Duster has 3.55's with 28" tires. I can be rolling along at 20 or 30, nail the throttle & all hell breaks loose. Although I have a stroker small block that thinks it's a big block.
 
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