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03-09-2017, 02:29 AM | #1 |
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Join Date: Jan 2014
Location: Sturgeon county alberta
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Ls swapped rear end question
Hey fellas, new to the site have a 1967 C10 I've been building for quite some time, stock chassis, carb'd 6.0 ls lq9, stock crank and rods, hyperutetic pistons @ 10.5:1 comp, ARP bottom end, 229/236 cam on a 108 lsa with the ls3 heads, runnin a single plain intake. Engine dynoed at 556 hp at 6500 rpm.. M21 trans, currently has 3:08 but I want somethin a bit peppier. Truck mostly will be driven around town and taken to the track every now and then. Wondering what you guys would recommend for a rear end gear, 3:73 or a 4:10. Truck has 29x18.5 Mickey Thompsons, any input is appreciated!!
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03-09-2017, 09:31 AM | #2 |
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Join Date: Mar 2005
Location: 10-Uh-See
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Re: Ls swapped rear end question
That engine will love the 4:10's, but not sure how much the transmission will help on the freeways. 3.73's would certainly make it peppier, and still do good at highway speeds.
I run 4:10 in my carbed LS1 with a similar cam, but I'm using a 700R4 with overdrive.
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03-09-2017, 09:43 AM | #3 |
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Location: Liberty, & Garden City S.C. , U.S.
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Re: Ls swapped rear end question
My 6.0 with 4l80e over drive the 4:10 are good.
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03-09-2017, 12:28 PM | #4 |
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Re: Ls swapped rear end question
I like 3.73 for the street unless it is a 4x4 with big tires.
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03-09-2017, 01:10 PM | #5 |
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Location: Redmond, WA
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Re: Ls swapped rear end question
4.10s here with a 4L80E (overdrive), it's about right. Lots of gear in town. I wouldn't go much more than 3.55 or at most 3.73 without overdrive though. Just me.
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03-09-2017, 02:00 PM | #6 |
The Older Generation
Join Date: Aug 2006
Location: Montezuma, Iowa
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Re: Ls swapped rear end question
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Unfortunately the M21 is a standard car 4 speed with no OD so 4.10's would be a bit low. The 3.73 would work great for that application and that is what I would recommend..... Just my 2¢ worth. LockDoc
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03-09-2017, 06:49 PM | #7 |
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Re: Ls swapped rear end question
I have 3.73's with a 29" tire and a 4l60e. I think its perfect. Stock LS1, though, and I already cant get any rear traction.
Depends on how much time you plan on spending at the track. I'd go 3.73's with or without O/D but my truck is much more about just enjoying the cruise these days.
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03-09-2017, 08:56 PM | #8 |
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Join Date: Nov 2011
Location: Williamsburg, VA
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Re: Ls swapped rear end question
With 556hp on tap I think a 3:55 would be a good setup. Your gonna have a hard time not blowing the tires off regardless of your gearing, but the deeper you go the less traction you're gonna have.
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03-09-2017, 09:31 PM | #9 |
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Location: Bigfork, Montana
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Re: Ls swapped rear end question
X5 on 3.73, if the trans had OD I might go 4.10
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03-10-2017, 10:08 AM | #10 |
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Re: Ls swapped rear end question
Agree , plus most of these trucks came with that gear , you'll want a posi
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