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#1 |
Account Suspended
Join Date: Apr 2013
Location: Belton, tx
Posts: 51
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Best rear gears for 700r4
What is the best rear end to run behind a stock 350 with a 700r4 auto? Most of my driving will be at hwy speeds. Will a 3.08 be ok?
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#2 |
Senior Member
![]() Join Date: Apr 2008
Location: Franklinton NC
Posts: 1,309
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Re: Best rear gears for 700r4
Should be fine. The 700r4 has a real low first gear so take off shouldn't be too bad. Depending upon your tire size you may actually end up with a lower rpm at highway speeds than you would like. I say try it then adjust if you aren't happy.
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#3 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: Best rear gears for 700r4
most guys over the years have had very bad results and an actual decrease in fuel milage when useing a 700r4 and 308 rear gears// where the guys with the 700r4 and the 373 get best results and fuel milage increases
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#4 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,151
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Re: Best rear gears for 700r4
3.42 is the best ratio with tall tires for a mixed use. If you are pulling more, then maybe 3.73.
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'83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project |
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#5 |
Registered User
Join Date: May 2013
Location: Central NC
Posts: 830
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Re: Best rear gears for 700r4
I have 3.08 gears, 700r4 trans, 255/70/15 tires, perfect from 60 mph up.
Around 55mph it feels like it is lugging a bit but my "RV" cam doesn't care. I like it, I can't say they are the "best" gears as I haven't run it with any others to compare. My mileage went from 11 mpg with the saginaw 3 speed to around 18 mpg overall (that was with 235/70/15 tires, haven't checked it since I upgraded). Can't speak for others though.
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1972 Cheyene C-10 "Ole Green" My Grandfathers truck (early 70's to 1983) My first vehicle (1983) Original 350 (3 rebuilds) 700R4 from Bowtie Overdrives ![]() |
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#6 |
Registered User
Join Date: Aug 2013
Location: waynesville georgia
Posts: 164
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Re: Best rear gears for 700r4
saginaw i now thats for 3 on tree what is saginaw mean
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#7 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,118
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Re: Best rear gears for 700r4
X 2 especially with a 28/29 inch tire.
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#8 |
Registered User
Join Date: Jul 2007
Location: Silverdale, WA
Posts: 263
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Re: Best rear gears for 700r4
From what i've seen people on the site using, a lot of them do not like the 3.08 because of to sluggish on the highway. Most seem to use 3.73's
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#9 |
Senior Member
![]() Join Date: Aug 2008
Location: Cedar Park, Texas
Posts: 7,500
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Re: Best rear gears for 700r4
3.73
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#10 |
Old member
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
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I run the 700 r4 with 4:10's and get 16-18 MPG depending on how fast I'm running. At Highway speed (70MPH) I'm turning around 2300RPM's.
I like the way it runs and it performs well for a 305! ![]() ![]()
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1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 ![]() Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
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#11 |
Watch out for your cornhole !
![]() Join Date: Jun 2003
Location: Azle, Texas
Posts: 14,162
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Re: Best rear gears for 700r4
Literally over 75 percent of the 2wd 88-98 trucks that were V8 and 700r4/4L60/e overdrive equipped came stock with 3.42 gears. Perfect ratio. GM got it right on that one.
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#12 |
Registered User
Join Date: Oct 2009
Location: Lufkin Texas
Posts: 171
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Re: Best rear gears for 700r4
I am currently running 3.08's and my truck don't like it at anything below 60 mph, I am in the process of switching to 3.73 .
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1965 Chevy Suburban 2003 Chevrolet S10 2011 Harley Streetglide |
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#13 | |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,858
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Re: Best rear gears for 700r4
Quote:
That's the sweet spot. 3.42s weren't offered in these trucks back when needs (for the most part) were different from now. 3.08-3.73 leaves a wide gap and 3.42s fill it perfectly. It's a great ratio for hiway with or without O/D,yet spill has grunt. I'm building my '67 with an M22 and 3.42s and it's a hiway machine who's bed will get used. When I can afford it,a Gear Vendors will go in. This ratio will work either way. I know this is manual/no overdrive talk,but this give perspective on the the range of ratios we're talking. The truck I helped my neighbor with ('68 SWB) has a 4spd and he didn't want it to suck the gas too hard. He went with 3.08s...hated it. Changed to 3.42s and it's good. Now he's got a ZZ3 in there and realizes he just wants a hot rod and,no matter what,it's going to like gas and he's not going to commute or travel in it. So,he's wanting 3.73s now for bit more grunt. If it was me,now,I'd be swappin' 4.11s!! ![]()
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#14 |
The Older Generation
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Location: Montezuma, Iowa
Posts: 25,521
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Re: Best rear gears for 700r4
-
So basically the only way to get 3.42's is to use the later, wider rear end and weld on new mounting pads? LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#15 |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,200
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Re: Best rear gears for 700r4
3.73's are perfect.
The overdrive in the trans brings it back as though they are 3.42's. K
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Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
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#16 |
Watch out for your cornhole !
![]() Join Date: Jun 2003
Location: Azle, Texas
Posts: 14,162
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Re: Best rear gears for 700r4
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#17 | |
The Older Generation
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Location: Montezuma, Iowa
Posts: 25,521
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Re: Best rear gears for 700r4
Quote:
Thanks Kevin.... I checked with my local independent mechanic and he said it would run around $100 to install the gears. I'm not sure I want to invest $300 to put 3.42's in the Burb... I'm just a tight a$$ I guess... ![]() LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#18 | |
Its a Truck Thing......
Join Date: Dec 2004
Location: Sierra Vista, Arizona
Posts: 3,159
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Re: Best rear gears for 700r4
Quote:
Smitty
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71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 71 C20 Longhorn/Ole Yellor 69 C30 Former Motor Home, Flat Bed time |
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#19 |
Account Suspended
Join Date: Apr 2013
Location: Belton, tx
Posts: 51
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Re: Best rear gears for 700r4
Is there a stock 3:42 6 lug rearend option for a 70 model? Thought only 3.08, 3.73 or 4.10 were available
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#20 |
Registered User
![]() Join Date: Apr 2013
Location: Gainesville, TEXAS
Posts: 658
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Re: Best rear gears for 700r4
350 FI / 4L60E / 3.08's / 30x9.5 tires great setup; take off is not a problem and at speed it works perfectly even with 6000 to 7000 lbs in tow in OD in the hills.
cruising speed of 70 MPH, rpm's are only 1650-1700 and fuel mileage is well above 17 MPG (unloaded)
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1972 Chevrolet Cheyenne LB 1/2 ton finished restoration/rebuild 1995 350 throttle body FI, 4L6E (running on modified GM wiring harness) 3.08 posi rearend, factory A/C on 134A, p/s, p/b, late 70's power windows and locks and cruise, speakers in the dash + 6x9's behind the seat, factory tilt, 40 gallon fuel tank in the bed with integrated tool box, air assist bags on the rearend, sway bar up front and much more. 1972 chevrolet SNB finished 2002, 350 TB FI, TH400, factory A/C, p/b, p/s, (FOR SALE) 1969 Chevrolet 1 ton in work, home made PTO dump bed extended frame, 350 CI , 1972 Chevrolet 3/4 ton suburban future project 1972 Chevrolet 3/4 ton p/u maybe a project one day 1966 Toyota Landcruiser my playtoy |
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#21 |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: Best rear gears for 700r4
A 3.08 will lug around town with that trans. TX had it right when he said 3.48 is optimal but failing that try a 3.73. Below are the RPM vs MPH for a 700 R4 for the 3.08, 3.48 and 3.73 in that order
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#22 |
Registered User
Join Date: Mar 2001
Location: Paradise TX USA
Posts: 1,200
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Re: Best rear gears for 700r4
My son's 71 GMC with a 350, 700R4, and 3.08 gears is a bit sluggish for my liking. We will probably change to 3.73 sometime in the future.
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"Negative people always seem to have a problem for every solution" |
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#23 |
The Older Generation
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Location: Montezuma, Iowa
Posts: 25,521
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Re: Best rear gears for 700r4
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I changed the 3.08 to a 3.73 in the '69 Suburban. Made all the difference in the world.... it has a 2004r OD trans in it. Averaged 16 mpg on a 550 mi round trip to Kansas City, MO last weekend. I'm lovin' it... ![]() LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#24 |
Registered User
Join Date: Apr 2010
Location: Everett, WA
Posts: 504
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Re: Best rear gears for 700r4
My '89 C1500 has a 350 FI, 700R4 and 3.08s in the rear with 31in tires on it.
Thinking of going to a 3.73 since its got a bigger tire on it. |
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#25 | |
The Older Generation
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Location: Montezuma, Iowa
Posts: 25,521
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Re: Best rear gears for 700r4
Quote:
My Burb has 31's on it too. LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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