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#1 |
Registered User
Join Date: Mar 2011
Location: Bakersfield Ca.
Posts: 417
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307 ring and pinion
I have a 3.73 posi from the factory and want to put in a 3.07. Does any one know if i have to change the posi carrier out? Thanks mark
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#2 |
1965 Chevy C10, 2005 4.8L/4l60
![]() Join Date: Aug 2004
Location: DFW Texas
Posts: 8,549
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Re: 307 ring and pinion
I dont believe you do, however you will need to make certain what series the carrier is, 3 or 4 ( im guessing 4) and you wont be able to use it since 4 series only goes to 3.73.
Good luck. You could call randys ring and pinion to find out. Have your rear end info handy.
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Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 ![]() ![]() ![]() support our troops! |
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#3 |
60-66 Nut
![]() ![]() Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,254
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Re: 307 ring and pinion
Yes you will have to change the carrier to a 3 series for 3.42 gears and higher. The 4 series carrier works with 3.73 gears and lower.
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#4 |
State of Confusion!
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Location: Gulfport, MS USA
Posts: 47,489
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Re: 307 ring and pinion
When I did my 64, I had an entire 3:07 assembly from a 72. The rear end shop had to do a couple things to match up the 64 axles & all with the 72 stuff. Something about the spline counts are different, which might be the series difference mentioned above. There was also some bearing difference. I can';t remember what else he mentioned.
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
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#5 |
Registered User
Join Date: Mar 2011
Location: Bakersfield Ca.
Posts: 417
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Re: 307 ring and pinion
Thanks guys for the info.
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#6 |
Registered User
Join Date: Jan 2013
Location: Las Vegas, NV
Posts: 1,857
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Re: 307 ring and pinion
A 3.73 to 3.07 only drops <500 rpm on 28 inch tires. This can be done with taller tire. Look at a rpm chart.
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1962 shortbed 408cui small block, TKO 600 5-speed, bagged Porterbuilt suspension. 18" Salt Flats http://www.cardomain.com/ride/332579...t-c-k-pick-up/ http://67-72chevytrucks.com/vboard/s...d.php?t=560081 |
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#7 |
Registered User
Join Date: Mar 2011
Location: Bakersfield Ca.
Posts: 417
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Re: 307 ring and pinion
Thanks for that information but the wheels and tires are new. I really like the old 15"
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#8 |
Registered User
Join Date: Apr 2016
Location: san diego ça
Posts: 121
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Re: 307 ring and pinion
Is that your engine-trans set up in picture? If so I would not worry about having 3.73 gears with that overdrive trans, it will work quite nicely I've done it several times
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#9 |
State of Confusion!
![]() ![]() Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 47,489
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Re: 307 ring and pinion
![]() Down here in flat lamd 3.07 with OD sows OK, but you start hitting some hills it does want to kick in and out of OD alot with the 3.07
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
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#10 |
60-66 Nut
![]() ![]() Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,254
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Re: 307 ring and pinion
I agree. 3.73 gears is just about perfect for most applications with an OD trans. I would not go any higher than 3.42's, and only if you have tires no taller than say 235/75R15's. Lower rpm's is not always better. The engine needs to operate in it's power range. You currently have a 3.73 gear with a posi, which is a very desirable combo. I would definitely drive it first and see how you like it.
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Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE |
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#11 |
1965 Chevy C10, 2005 4.8L/4l60
![]() Join Date: Aug 2004
Location: DFW Texas
Posts: 8,549
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Re: 307 ring and pinion
I had 3.08 before i rebuilt my 12 bolt. I put 3.73's and limited slip/posi in it. The 3.08 were fine at 40mph plus as long as it was flat-ish. Taking off was a little sluggish and very sluggish on medium to large hills, like over passes and such. This is what made my mind up to go 3.73, i also called randys ring and pinion and they were very helpful on the decision.
Good luck!
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Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 ![]() ![]() ![]() support our troops! |
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#12 | |
Registered User
Join Date: Mar 2011
Location: Bakersfield Ca.
Posts: 417
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Re: 307 ring and pinion
Quote:
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#13 |
Registered User
Join Date: Jan 2013
Location: Las Vegas, NV
Posts: 1,857
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Re: 307 ring and pinion
I run a 3.73 with a 28.5 (295 / 45 / 18 ) with a .67od at 2000rpm or little less at 75. Here is a chart. Tires tend to be cheaper than gear swapping.
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1962 shortbed 408cui small block, TKO 600 5-speed, bagged Porterbuilt suspension. 18" Salt Flats http://www.cardomain.com/ride/332579...t-c-k-pick-up/ http://67-72chevytrucks.com/vboard/s...d.php?t=560081 |
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#14 |
Registered User
Join Date: Feb 2012
Location: pleasant valley--placerville ca
Posts: 3,039
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Re: 307 ring and pinion
what trans do you have and how tall are the tires? I had a 56 Nomad with a 468BB with a 700r o/d with 3.08 gears and they were fine. Now if you never want to take it out of o/d i guess you wouldn't want 3.08/307's
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1961 chevy K10 my build is------------61K10 build |
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#15 |
Registered User
Join Date: Mar 2011
Location: Bakersfield Ca.
Posts: 417
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Re: 307 ring and pinion
Its a 4l60, My tires are 255 60 15 about 27" tall
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