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#1 |
Senior Member
![]() Join Date: Feb 2008
Location: Denver, CO
Posts: 252
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Differential, Transmission & Motor Combo Opinions Needed
For the last year and a half, like a lot of us, I have been collecting parts to re-do my 72 SWB Cheyenne Super. I have come to the conclusion I have so many parts that maybe I should just build a new truck. So, I purchased a new shortbed frame and am having a lot of the parts powder coated and/or replaced. In cleaning up the rear end, I looked up the code and found that it is a 3.07. Here's my dilemna, I purchased a slightly used (200 mi.) HO 350 GM crate motor (330 HP) and my initial thoughts were to put in a 700r4 tranny. Now that I know I have a 3.07 rear end I have read and heard that combination isn't a good one. I would love to hear opinions on which way I should go. I live in the city and most of the driving with this truck will be short interstate (25 mi. plus/minus) and just cruising on city streets. One other thing I might mention, I am at 5280 feet above sea level.
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#2 |
Watch out for your cornhole !
![]() Join Date: Jun 2003
Location: Azle, Texas
Posts: 14,162
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Re: Differential, Transmission & Motor Combo Opinions Needed
My favorite combo is a 350, TH350, and 3.07 gears. I've run a bunch of different ones, but for me, this is the one I always am most satisfied with.
For me, it's a lot about economics too though. A 3.07 rear is usually cheaper to buy than a 3.73 (they are in more demand it seems), and a TH350 is way cheaper than a 700R4 is.
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I'm on the Instagram- @Gearhead_Kevin |
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#4 |
Watch out for your cornhole !
![]() Join Date: Jun 2003
Location: Azle, Texas
Posts: 14,162
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Re: Differential, Transmission & Motor Combo Opinions Needed
In my current shortbed:
Bone stock 170k mile 350 from a 77 model truck. Edelbrock performer intake, 600 vac secondary Holley, stock ramshorn exhaust manifolds, dual glasspacks Bone stock 170k mile never touched TH350 3.07 rear diff with 275/60/15 tires. From a standing stop, it will burn both tires through first and about 1/2 way through 2nd gear. Not a hot rod at all, but I've never been dissapointed with it. I get 12 mpg every tank.
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I'm on the Instagram- @Gearhead_Kevin |
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#5 |
Registered User
Join Date: May 2005
Location: PA
Posts: 2,696
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Re: Differential, Transmission & Motor Combo Opinions Needed
From your description of driving type, I'd go for 3:73's.
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#6 |
Registered User
Join Date: Jun 2008
Location: South Florida
Posts: 11,375
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Re: Differential, Transmission & Motor Combo Opinions Needed
My combination is a Small Block 406 (420 Horse Power to the wheels) with a built TH350 and 373 gears. My truck does not get driven alot but maybe 100 miles a month give or take so fuel economy is not important to me. Truck is stupid fast I can not get on the throttle at no speed less than 50mph because it breaks the tires out of control loose. I am very happy with my combo...
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Get your facts first, and then you can distort them as much as you please!!!!!. Sylvester's build thread >>>http://67-72chevytrucks.com/vboard/s...ht=big+rebuild |
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#7 |
*************
![]() Join Date: Apr 2005
Location: Pensacola, FL
Posts: 17,846
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Re: Differential, Transmission & Motor Combo Opinions Needed
The 700 and 3.73 gears are hard to beat. You might as well do it now and have the flexibility later if your driving style changes.
R/ PS Where are the pictures? ![]()
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
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#8 |
Registered User
Join Date: Apr 2009
Location: Valley Center, Ca.
Posts: 37
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Re: Differential, Transmission & Motor Combo Opinions Needed
I have run a 350/700R4 w/3.42 posi for well over 100000 miles. I pull hills, Zip down the Freeway and tow heavy (14' enclosed & Car trailer) @ 70mph it would tach about 2400rpm w/26" tall tire(295/35R17). It gives you an all around use. 700R4 gives you a 5% lower 1st & 2nd gear over a TH350/TH400.
Although a TH350 w/3.07 would be the less expensive, it is all what you want to spend. A quality 700R4 will set you back 1800.00+ now days. I purchased mine from the Toy Shop. I have used 4 of these for different friends rides, all are still in service. Quality Fluid & Coolers are a Must! I use a Hydrotex HytorqueZ and a B&M Super Cooler, routed thru the Radiator cooler then thru the external cooler. But it all comes down to the $$$$$$$$ you want to spend. ![]() |
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#9 |
Formerly- 1972SuperCheyenne
![]() Join Date: Oct 2008
Location: Wake Forest NC
Posts: 5,782
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Re: Differential, Transmission & Motor Combo Opinions Needed
I love a 700r4 and 3.73 combo. Great all around combo.
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--Josh My Build Thread:http://67-72chevytrucks.com/vboard/s...d.php?t=799218 A good crossthread is better than Loctite any day. Life is not about what you have, but who you have to share it with. |
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#10 |
newbie
Join Date: Feb 2009
Location: Wise Virginia
Posts: 122
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Re: Differential, Transmission & Motor Combo Opinions Needed
whats the best diff for gas mileage?
Last edited by dga93; 05-17-2009 at 08:17 PM. |
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