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#1 |
Senior Member
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Location: Chesapeake, Va
Posts: 1,275
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overdrive opinion
alright guys lets hear it ...
a built 700r4 for around 2300 to 2500 or spend around the same amount maybe a little less for a gear vendor OD set up for my Th350???
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Mike 72 C-10 Cheyenne off frame resto and Upgraded to 4 wheel disk, Tilt, Dakota Digital Dash / Rear slider. 421 SBC / TH350 3000RPM Stall Progression Ignition /Holley 750 DP/3:73 gear Eaton Limited Slip unit / 2 1/2 exhaust glasspacks ![]() |
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#2 |
Registered User
Join Date: Jan 2015
Location: Austin, Texas
Posts: 269
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Re: overdrive opinion
Never knew there was an option for OD on a TH350? Is this an aftermarket option when rebuilding?
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#3 | |
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Re: overdrive opinion
Quote:
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Mike 72 C-10 Cheyenne off frame resto and Upgraded to 4 wheel disk, Tilt, Dakota Digital Dash / Rear slider. 421 SBC / TH350 3000RPM Stall Progression Ignition /Holley 750 DP/3:73 gear Eaton Limited Slip unit / 2 1/2 exhaust glasspacks ![]() |
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#4 |
Senior Member
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Location: North Texas
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Re: overdrive opinion
I'd sure consider the GV unit. Those things are very stout, and you don't have to worry about controlling a lock-up converter. In any gear you can click a switch and it will go into OD, essentially giving you 6 ratios to choose from behind a TH350. Or you don't have to touch a thing, and it will go into OD at some pre-selected road speed and drop out below that.
Please note the GV's .78 ratio won't lower your highway RPMs as much as the 700R4's .70 ratio. But I think .78 is actually a better ratio. It will decrease your highway RPMs from, let's say, 2500 to 1950. That's huge IMO. And you still have the TH350's nice 1st gear ratio, not the crazy low 1st gear in the 700R4.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 03-17-2021 at 11:10 AM. |
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#5 |
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Join Date: Mar 2006
Location: Latrobe, Pa. 15650
Posts: 344
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Re: overdrive opinion
I installed a Gear Vendors in my 69 CST LB and love it. I even had a one piece drive shaft made. I'm getting better miles to gallon too.
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#6 |
Senior Member
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Location: North Texas
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Re: overdrive opinion
TH350 trans? How do you use the OD? Auto-engage at xx mph or???
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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#7 |
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Re: overdrive opinion
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#8 |
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Re: overdrive opinion
I have 2 GVendors 1 behind a TH350 and 1 behind a SM465 both perform flawlessly.
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#9 |
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Location: washington
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Re: overdrive opinion
Sorry, I am voting for the 4l60. Or 700r4 if you prefer.
If you add the overdrive to the 350 you still have a used transmission. You can split shift with the GV unit but who does that except for heavy loads? I just think it keeps it simpler. Rick |
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#10 |
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Location: Harrison, Arkansas
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Re: overdrive opinion
I have a 700R4 in my Longhorn behind a big block. I also have a new GV in the box and the now fresh 400 turbo that came out of the truck.
lf the 700R4 ever bites the dust, I will put the turbo 400 and GV in it.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#11 | |
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Re: overdrive opinion
Quote:
Not only that, but once the TV cable is correctly adjusted, any carburetor idle speed adjustment that you may have to do periodically (like winter/summer) requires a re-adjustment of the TV cable. But again, with EFI, it shouldn't be an issue. I doubt that most transmissions shops understand the above unless they are familiar with non-factory type installations On another note, how do you feel about the ratio spread between 1st and 4th gear and then converter lock-up? On a friend's car, a 37 Chevy with a 350, 1st gear is so low that the 1-2 shift happens after a couple car lengths. 4th gear seems too tall, especially when the converter locks-up. In fact, he keeps the shifter in 3rd gear until he gets on the highway, and controls lock-up with a dash-mounted switch. But again, all that may be due to not having a vacuum switch to control the trans, and whatever else a stock installation has. His car has a 3.36 axle and 29" tires.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 03-17-2021 at 11:09 AM. |
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#12 | |
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Join Date: Apr 2001
Location: DALLAS,TX
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Re: overdrive opinion
Quote:
Heck, the math says that combo is only moving along @ a tick over 2700 @ 70mph in 3rd so that 700r4 puts him kind-of under the target zone of a traditional warmed-up sbc @ just under 2100rpm @ 75mph unless it's a low rpm/torque built motor. For C10's, I'd want minimum 2200rpm & be good w/24-2500 @ ~75mph. As far as 700r4 vs. a 3spd auto/GV OD for someone that doesn't personally have experience with/or 'have a 'guy' for transmission builds? I'd do the GV for fewer headaches & better rpm splits between gears. You're likely to spend the same amount (well built 700r4 vs GV) on initial purchase unless you build one yourself so that's a wash. The finicky TV cable adjustment is always a concern when poking around under the hood (not a big deal on the average Joe/Janes all-stock/EFI'd mass produced set-up). Not that the GV doesn't have it's drawbacks though (don't put it in reverse when it's engaged or it will be done). The GV gets the nod for strength when OD is engaged.
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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#13 |
Senior Member
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Location: Chesapeake, Va
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Re: overdrive opinion
If you add the overdrive to the 350 you still have a used transmission.
what does that mean "Used"?? I built it myself and not worried about it being used and works great only got about 3500 miles on it ... I think i will go with the GV unit , I am not interested in the whole split shifter idea just the OD function on the innerstate.
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Mike 72 C-10 Cheyenne off frame resto and Upgraded to 4 wheel disk, Tilt, Dakota Digital Dash / Rear slider. 421 SBC / TH350 3000RPM Stall Progression Ignition /Holley 750 DP/3:73 gear Eaton Limited Slip unit / 2 1/2 exhaust glasspacks ![]() |
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#14 |
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Join Date: Jul 2018
Location: Catskill Mountains,NY
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Re: overdrive opinion
GV without a doubt specially if you do any towing I burned up two 700r4s on my 87 Suburban back in the 90s . First one the original at about 90k , I had bought the truck with 65k and it never towed prior to my ownership. Replaced with a goodwrench rebuilt with the upgrades ,that one lasted to 155k . I sold it after the second one was replaced and bought a new 2500 Savanna 12 passenger van in 98 . That towed till I bought my Dodge in 07 without a problem .
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Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary. |
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#15 |
All about them K’s
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Re: overdrive opinion
One problem, the 700r4 isnt known for great gear ratios or to hold up to any real amount of HP without being built up, I believe the th350 is stronger simply for the fact that there’s no overdrive to hunt in and out of and generate extra heat and wear and tear. Sorry I’m likely a bit cynical as I’ve been bitten by a couple of 700R’s and I have nothing good to say about them. I get what your saying, but I really think in the long run the gear vendors is a better path.
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's ‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue ‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0 ![]() Last edited by 57taskforce; 03-17-2021 at 11:57 PM. |
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#16 |
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Join Date: Apr 2011
Location: Klein Texas
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Re: overdrive opinion
That's why I chose a 4L60. I could buy cores for less than $200 and rebuild them myself
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My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe |
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#17 |
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Join Date: Jul 2012
Location: Whitehorse yukon
Posts: 1,218
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Re: overdrive opinion
Need the ecm i am going 4l80e tougher tranny
With some sensors added a stock ecm /pcm you can add it to a carberated truck I seen a few threads on this setup I never fully followed up as I am going fuel injected on the trucks that are getting the slush box As for a 700r4 depends on how you drive Drive it hard and spirited may want to look at a tougher tranny take easy and mall crawler it should last a decent amount of time you also need to consider the torque output you have this is the reason why gm never put a 700r4 behind a big block |
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#18 | |
Registered User
Join Date: Apr 2001
Location: DALLAS,TX
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Re: overdrive opinion
Quote:
__________________
67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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#19 |
Senior Member
![]() Join Date: Mar 2015
Location: washington
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Re: overdrive opinion
[QUOTE=SCOTI;why gm never put a 700r4 behind a big block .[/QUOTE]
GM didn't do it but I did. Never had an issue. Big changes on two fronts. Fuel mileage went from 10 to 13 on the highway a 30% improvement. The noise in the cab dropped significantly. I was amazed at how much noise came from the motor. Rick |
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#20 |
Post Whore
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Location: Portland Oregon
Posts: 11,086
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Re: overdrive opinion
A couple of points on the 700r4.
If your looking to maximize fuel mileage the 700r4 has an edge due to the lock up converter. To improve the life span of the unit only shift it into overdrive on the highway above 45 mph for distances longer than a mile. When the transmission is continually shifting in and out of OD extra heat builds up to the detriment of the transmission. 700r4s are prone to hunting when driving in the 35 to 45 mph.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#21 | |
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Location: Harrison, Arkansas
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Re: overdrive opinion
Quote:
I had a 55 Chevy and a 65 Chevelle with 2.73 gears and a 700R4. Overdrive was absolutely Interstate only. I think 3.42 is minimum rear gear for an overdrive to operate properly. Especially with a small block.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#22 | |
Senior Member
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Location: North Texas
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Re: overdrive opinion
Quote:
As for SCOTI's comments about the car's "tall" gearing, he's right on the money. A 3.73 axle would make a lot more sense. BTW, I was mistaken about tire height. It's actually around 27.5", but still, that 3.36 axle is too tall.
__________________
Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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#23 |
Registered User
Join Date: Oct 2016
Location: Dallas Texas
Posts: 3,077
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Re: overdrive opinion
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67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
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#24 |
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Location: washington
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Re: overdrive opinion
"700r4 has an edge due to the lock up converter"
Don't forget you can use a 350C. They also have lock up converters. |
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#25 | |
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Join Date: Apr 2001
Location: DALLAS,TX
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Re: overdrive opinion
Quote:
If you're going to quote someone/something, make sure you tag the correct person.
__________________
67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. Last edited by SCOTI; 03-18-2021 at 01:02 AM. |
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