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Old 04-27-2005, 03:16 PM   #1
72GMC51
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3:73 or 4:11

Well time to do the rear end, I am going with a Eaton posi new bearings etc, the question I have is do I keep the 4:11s or do I go to 3:73? I have a 350 bored 30 over, with a mild cam (RV2) headers etc, and a 700r4 trany.
Whats your experiance/opinion
Thanks
JC
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Old 04-27-2005, 03:31 PM   #2
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I have 3:73's cruise rpm is good in OD, tends to shift too soon round town so stay in 3rd. Maybe this rpm calculator can help you make a decision. http://www.700r4.com/speedoCalc/rpmcalc.shtml
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Old 04-27-2005, 05:15 PM   #3
67ChevyRedneck
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If you want driveability, decent gas mileage, and lower highway rpms I'd go with the 3.73. My truck does just fine with it (stock 350/700R4/3.73). You can even tow heavy loads with it. I've always considered a 4.11 to be a super heavy hauling gear or a gear you would use for acceleration at a track. My truck does the same as 'wings, I have to leave it in 3rd around town, tries to shift into OD at about 35-40mph. It's up to you but if you have the 3.73 I'd go with it.
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Old 04-27-2005, 05:59 PM   #4
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I've had 4:10s for about 11 years..

It depends on how much highway driving you're going to doing. If you live in town and that's your cruise/play area, then keep the 4:11s, They're fun. if you're going to be on the highway at any kind of a regular timing, then go the higher gears, They really chew the fuel up and the Motor's taching pretty high even at 55....

I'm contemplating on switching over to 3:5s I have 35 miles of 65 MPH highway just to get to town...
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Old 04-28-2005, 08:35 PM   #5
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Well the 4.10s it is, thanks chickenwing for the rpm calculator link, it really help. Most of my driving will 40 - 60 and I like the rpm range.
JC
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Are they ever really finished
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Old 04-29-2005, 03:16 AM   #6
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A lot will depend on what size rear tires you are running. 50-series or 38" gumbo
mudders???

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Old 04-29-2005, 05:38 PM   #7
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JC
Quote:
Originally Posted by rwgregory
A lot will depend on what size rear tires you are running. 50-series or 38" gumbo
mudders???

rwgregory
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Old 04-29-2005, 06:16 PM   #8
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3:42

Quote:
Originally Posted by RON WOODGEARD
I've had 4:10s for about 11 years..

It depends on how much highway driving you're going to doing. If you live in town and that's your cruise/play area, then keep the 4:11s, They're fun. if you're going to be on the highway at any kind of a regular timing, then go the higher gears, They really chew the fuel up and the Motor's taching pretty high even at 55....

I'm contemplating on switching over to 3:5s I have 35 miles of 65 MPH highway just to get to town...
I am going to go with 3:42's and a700R4 for my 396/350 HP engine. I've been told that the 396 will chew up the 700R4 if I hammer it often, anyone have anyexperience with that . I'm old and just punch it once in awhile.
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Old 04-29-2005, 06:57 PM   #9
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I run 4.10 gears and the 700R4 with 26.5in tires, I have no issues cruising the highways with the gears, I have also run the 3.73 gears with these same profile tires but going into OD with the lockup really took a lot of of the engine, the 4.10's kept a lot of that Tourqe still there. If you just using the truck for tooling around and arent looking for an advantage point at the lights or arent really going to be pulling any heavy loads or heavy trailers go with the 3.73. If on the other hand you like the acceraltion factor or doing some heavy hauling the 4.11 gears arent all that bad with the OD trans, cruise at 70 with 28in tires is going to be around 2400rpm
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Old 04-29-2005, 08:07 PM   #10
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My truck has a stock 350/TH400/4.11's, running on four 31/10.5/15's, and it does great around town. I don't like driving it on the highway, it's running at least 3200rpms at 65. And that rear end whines like he!! after 60 anyway. When I finally wear down those 31's, I'm going with 235/85/16 BFG's out front, and 33/12.5/16 BFG All-Terrain T/A's out back.
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