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Re: Is a 4.30 rear end right for me?
[Re: GTXKen]
#104704
08/14/08 03:44 PM
08/14/08 03:44 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
 W/a 4.30 and a 27" tire, in an ideal world with no converter slippage at highway cruise, you'd be doing 3200rpm at 60mph. Can you live with that? Make sure you make that decision before you pull the trigger. Play around with this calculator here if you need help deciding.
http://vexer.com/68rt/speed.html
useful tool,(and fun) thanks for sharing
Thats AWESOME!
What is typical converter slippage at the high end? I cant see that there is NO slippage. there has to ve some
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Re: Is a 4.30 rear end right for me?
[Re: Black_Sheep]
#104706
08/14/08 04:06 PM
08/14/08 04:06 PM
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Joined: Apr 2003
Posts: 3,968
North Riverside IL & Lowell IN
GTXKen
super gas
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super gas
Joined: Apr 2003
Posts: 3,968
North Riverside IL & Lowell IN
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Quote:
Quote:
The reason I was thinking of 4.30s over 4.10s or 3.91s is that you can find so many of them
Probably because the seller figured out that 4.30:1 was too much gear for their liking... 
That sounds likely
I am running 3:55s and I couldn't imagine going to anything more than 3:91s on the street. Most of my driving is around town with some occasional highway driving.
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Re: Is a 4.30 rear end right for me?
[Re: VITC_GTX]
#104708
08/14/08 06:58 PM
08/14/08 06:58 PM
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Joined: Jan 2003
Posts: 292
Atlanta
DartGTX
enthusiast
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enthusiast
Joined: Jan 2003
Posts: 292
Atlanta
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I have 3.55's and a fairbanks 2600-2800 stall converter, this works very well with my 284/484 with "fast-bleed" lifters. It is a GREAT combo and has TONS of low end torque. 440's don't need gear, just the right combination.......... Like many others have suggested, get a good 2800 converter first. If your idle vacuum is less than 13" at idle I would also recommend fast-bleed lifters to smooth it out and ADD torque. Good luck, 
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Re: Is a 4.30 rear end right for me?
#104709
08/14/08 07:10 PM
08/14/08 07:10 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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Quote:
Thats AWESOME!
What is typical converter slippage at the high end? I cant see that there is NO slippage. there has to ve some
Yeah I know, that calculator is great. I use it all the time. Best of all it was made by a moparts member, tho I can't remember his user name off hand.
I'm not 100% sure on the converter slippage issue. I think a stock converter is around 95% and aftermarkets are around 90 for a good quality unit, and low 80's for a cheapie. There's a slider bar on there for efficiency so you can experiment.
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Re: Is a 4.30 rear end right for me?
[Re: MoparforLife]
#104712
08/15/08 09:12 PM
08/15/08 09:12 PM
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Joined: Sep 2006
Posts: 3,011
Sac, CA
mopowers
master
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master
Joined: Sep 2006
Posts: 3,011
Sac, CA
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Quote:
For 100% street driving you will be much happier with a 3.91 than a 4.30. 4.30 is pretty deep for a street car. 3.91 at 60 mph will spin your engine approx. 3000. 4.30 a lot more than that.
The 4.30s would spin the engine 300 more RPM (3300)in your senario. Whether or not that is "a lot more" is up to interpretation.
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Re: Is a 4.30 rear end right for me?
[Re: mopowers]
#104713
08/15/08 10:03 PM
08/15/08 10:03 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
Quote:
For 100% street driving you will be much happier with a 3.91 than a 4.30. 4.30 is pretty deep for a street car. 3.91 at 60 mph will spin your engine approx. 3000. 4.30 a lot more than that.
The 4.30s would spin the engine 300 more RPM (3300)in your senario. Whether or not that is "a lot more" is up to interpretation.
Looks good on paper. In the real world 300-500 makes a big differnce and it usually doesn't work out that way. That 4.30 to me just wouldn't be that nice to drive until you put about a 30+ inch tire on. Deepest I would go is a 3.91. Been there done that.
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Re: Is a 4.30 rear end right for me?
[Re: MoparforLife]
#104714
08/15/08 11:50 PM
08/15/08 11:50 PM
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Joined: Jan 2003
Posts: 1,379
Houston,Tx.
Lee446
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,379
Houston,Tx.
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I have run 3.55, 3.91,and 4.30 on the street and track. I think you are on the right track by getting a quality converter in the 2800-3000 range. When I bracket raced my steet car, I swapped the chunks regularly and kept good records and the 4.30's were good for only 3-4 tenths with my combo. With a lot of torque, gears are not quite as critical, but deep gears just get to be a pain in the butt for all around driving. After years of experimenting and shelling ring gears at the track, I went to a Dana with 3.54's and have been very happy ever since. My .02.
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Re: Is a 4.30 rear end right for me?
[Re: DaytonaTurbo]
#104715
08/16/08 12:14 AM
08/16/08 12:14 AM
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Joined: Mar 2007
Posts: 3,287
West Coast, USA
jbc426
master
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master
Joined: Mar 2007
Posts: 3,287
West Coast, USA
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Quote:
http://vexer.com/68rt/speed.html
After nearly 18 years since the day I did it, this calculator gave me flashbacks of the time I had my 3.54 geared, 4-speed at 6000 RPM in 4th with 255-65 15's all around. I remember tunnel vision closing in around 135MPH, and the tunnel kept getting smaller the faster I went.
I thought I could hold it until it hit 6500 rpm, but when it hit 6000 prm, I took my foot out of it. Self preservation got the best of me. It wasn't until I got a rice rocket in the late 90's that I broke that personal top speed record.
Wow, what a rush. I'll always believe Mopars were made to dominate the half mile, as well as, the quarter. The real fun is just begining when you pass the quarter mile mark and bang it into 4th, the front end lifts back up and your glued to the seat! 
Thanks for the memories!
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Is a 4.30 rear end right for me?
#104716
08/26/08 10:24 PM
08/26/08 10:24 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
And you would be surprised at the gas milage I get. But I dont care because if I did I am in the wrong hobby.
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Re: Is a 4.30 rear end right for me?
[Re: Sledge_57]
#104717
08/26/08 10:50 PM
08/26/08 10:50 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
I like my 4.30's however if I wanted to drive 60mph on the freeway I'd go back to 3.91
Mines spins 3000 at 50mph with 275-60-15 tires and a 9 1/2" PTC 4200 converter. Cruisin at 60mph ain't happening for me with the 4.30's
i checked my 4.30s out this weekend. I can do 55 mph at 3000 rpm. but my converter stalls lower than yours- around 3200.
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Ron
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