best way to go overdrive? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

krue · 03-23-2003, 09:00 PM

1970 GMC 350 w/auto tranny, what's best swap to get overdrive?

sam's 72 · 03-23-2003, 10:26 PM

Depends on how much money you want to spend? The cheaper way is to go with a built up 700r4 or you can keep your th350 and go with an over drive unit, they run some where around $2200 to $3000, the overdrive unit bolts to the back of the th350, then the drive shaft bolts up to it. I don't have a link to a site that sells them, but someone on here probabley does.
My 2 cents worth.
Sam

gmc67swb · 03-23-2003, 10:57 PM

I JUST DID THE 5 SPD MANUAL. BUT SEEING AS HOW YOUR ALREADY AUTOMATIC, I WOULD GO THE 700R4 ROUTE. DON'T KNOW MUCH ABOUT THAT THOUGH.

mtdave2 · 03-23-2003, 11:06 PM

well, it depends.. to me the 700r4 is the LAST way to go.

the easy way to get the rpms down. tall tires, new rearend with 307s in it. but if your a hot rod like the lack of low end guts. this set up works great on the highway.

the next best, for ease of application, is something like gearvender. and aux trany. (this is the way i will go next)
they bolt right to your trany, all you need is some drive line work, and some wires. then you have a 6 speed auto. kick butt...

then you have the 5 speed. probably the absolut best overall way to get the best of everything.

700r4, if you feel like gambling. i hate these things. they do work great IF you get a good one and set it up right. i just have had several bad exsperances with these things. dont fool yourself, you cant do these cheap and have it ast.

disclaimer.....i have been wrong before.. but this is the way i see it!

Ackattack · 03-23-2003, 11:17 PM

I'd say t-56 with 4.10s out back

double overdrive will let you run that kind of gear and still pickup mileage. I don't think that would be the cheapest route though.

I'd say 700r4 for a cheap way to go.

krue · 03-23-2003, 11:17 PM

do you know of anyone who has the aux overdrive. Would like an idea on ease of installation, price, durability, etc. I am not a big fan of the 700 just from friends experiences with later model trucks

gmc67swb · 03-23-2003, 11:43 PM

PRICE ON THE GEAR VENDORS UNIT IS A TICK OVER $2000. FAR AS DURABILTY GOES, YOU CAN BEAT THE SH$T OUT OF IT. I'VE HEARD THEY'RE RATED TO OVER A 1000HP

Longhorn Man · 03-23-2003, 11:51 PM

look here for the facts on the gear vendors. http://www.gearvendors.com/commercial.html
If the $$ are there for this set up, it is by far the best way to do the overdfive route.

crazy longhorn · 03-24-2003, 12:05 AM

Its gonna be a big ouch on the wallet.....but the 400t is coming out of my longhorn, & a 6 spd richmond is going in

I have looked at all the overdrive options that I could think of, & the bottom line is I love rowing that stick. for the auto crowd, I think the Gearvendors would be the ticket(tough as nails). good luck,crazyL

Longhorn Man · 03-24-2003, 12:07 AM

Actually, i think the gear vendors can go on a stick shift too.

crazy longhorn · 03-24-2003, 12:11 AM

Yup, you are right Andy.......me just had a "brain fart"! its an old man thing

crazyL

1969 GMC · 03-24-2003, 12:11 AM

3 other OD manual transmissions (but these are truck, not car, so not for dragging):
-NV 4500 (5 spd)
-NV 5600 (6 spd)
-Clark 5 spd

mtdave2 · 03-24-2003, 01:22 AM

oh a 6 speed with a gearvender.... ooohhhh aaaaahhhhhhh oooooooooooo that would rule

**COBALT** · 03-24-2003, 01:57 AM

Screw the 700r4. I'm a TH400 guy. I'm saving my nickels and dimes for the overdrive unit...

IMHO

dmnall · 03-24-2003, 04:05 AM

Well I am thinking of trying to get a BW T56 or even Zexel T56(Same as BW but made by Texel), out of either a F-body or Vette.. Damn I just need to get a hold of the guy that goes around to all the shops in my area and he sells the tranny cores for $ 50 and the last one I saw from the guy just blew the syncros and lost 3rd gear... If I can get one w/ that just needs to be rebuilt, then I would be ecstatic especially w/ 5th gear being like .76 and 6th gear .50, add 4.10s and Damn you have one fast as hell truck that cruises at around 2000 rpms @ 80 Mph.. I can live w/ that, better then having 3.73 gears w/ TH400 tranny and spinning 3500 RPMs @ 80...

mtdave2 · 03-24-2003, 11:14 AM

http://www.rverscorner.com/info/auxtrans.html

thats a good review on the 2 most common aux tranys. i always want to know the down side to everything im looking at getting. this guy does a great job giving you the no b/s view of them.. i love stuff like this!

has any one on the board delt with these on our trucks?

oh , and im glad to see i am not the only one who doesnt like the 700r4. i have been feeling like the loan ranger here for a while...

cdowns · 03-24-2003, 12:18 PM

i'm running a 2004R that's been built up alot easier to install just move the crossmember and bolt it in no driveshaft mods needed so far i have 30thousand miles with no problems

03-23-2003, 09:00 PM	#1
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	best way to go overdrive? 1970 GMC 350 w/auto tranny, what's best swap to get overdrive?

03-23-2003, 10:26 PM	#2
sam's 72 Senior Member Join Date: Nov 2001 Location: Pasadena, Texas, USA Posts: 1,005	Depends on how much money you want to spend? The cheaper way is to go with a built up 700r4 or you can keep your th350 and go with an over drive unit, they run some where around $2200 to $3000, the overdrive unit bolts to the back of the th350, then the drive shaft bolts up to it. I don't have a link to a site that sells them, but someone on here probabley does. My 2 cents worth. Sam __________________ 72 LWB chevy truck. Pasadena, Texas

03-23-2003, 10:57 PM	#3
gmc67swb Registered User Join Date: Feb 2003 Location: Mesquite, Tx Posts: 396	I JUST DID THE 5 SPD MANUAL. BUT SEEING AS HOW YOUR ALREADY AUTOMATIC, I WOULD GO THE 700R4 ROUTE. DON'T KNOW MUCH ABOUT THAT THOUGH. __________________ GM 330HP/350, Magnuson 122HH, Tremec TKO 5spd

03-23-2003, 11:06 PM	#4
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,521	well, it depends.. to me the 700r4 is the LAST way to go. the easy way to get the rpms down. tall tires, new rearend with 307s in it. but if your a hot rod like the lack of low end guts. this set up works great on the highway. the next best, for ease of application, is something like gearvender. and aux trany. (this is the way i will go next) they bolt right to your trany, all you need is some drive line work, and some wires. then you have a 6 speed auto. kick butt... then you have the 5 speed. probably the absolut best overall way to get the best of everything. 700r4, if you feel like gambling. i hate these things. they do work great IF you get a good one and set it up right. i just have had several bad exsperances with these things. dont fool yourself, you cant do these cheap and have it ast. disclaimer.....i have been wrong before.. but this is the way i see it! __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban

03-23-2003, 11:17 PM	#5
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,524	I'd say t-56 with 4.10s out back double overdrive will let you run that kind of gear and still pickup mileage. I don't think that would be the cheapest route though. I'd say 700r4 for a cheap way to go. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

03-23-2003, 11:43 PM	#7
gmc67swb Registered User Join Date: Feb 2003 Location: Mesquite, Tx Posts: 396	PRICE ON THE GEAR VENDORS UNIT IS A TICK OVER $2000. FAR AS DURABILTY GOES, YOU CAN BEAT THE SH$T OUT OF IT. I'VE HEARD THEY'RE RATED TO OVER A 1000HP __________________ GM 330HP/350, Magnuson 122HH, Tremec TKO 5spd

03-23-2003, 11:51 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	look here for the facts on the gear vendors. http://www.gearvendors.com/commercial.html If the $$ are there for this set up, it is by far the best way to do the overdfive route.

03-24-2003, 12:05 AM	#9
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Its gonna be a big ouch on the wallet.....but the 400t is coming out of my longhorn, & a 6 spd richmond is going in I have looked at all the overdrive options that I could think of, & the bottom line is I love rowing that stick. for the auto crowd, I think the Gearvendors would be the ticket(tough as nails). good luck,crazyL

03-24-2003, 12:07 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Actually, i think the gear vendors can go on a stick shift too.

03-24-2003, 12:11 AM	#11
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Yup, you are right Andy.......me just had a "brain fart"! its an old man thing crazyL

03-24-2003, 12:11 AM	#12
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	3 other OD manual transmissions (but these are truck, not car, so not for dragging): -NV 4500 (5 spd) -NV 5600 (6 spd) -Clark 5 spd __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

03-24-2003, 01:22 AM	#13
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,521	oh a 6 speed with a gearvender.... ooohhhh aaaaahhhhhhh oooooooooooo that would rule __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban

03-24-2003, 01:57 AM	#14
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Screw the 700r4. I'm a TH400 guy. I'm saving my nickels and dimes for the overdrive unit... IMHO __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

03-24-2003, 04:05 AM	#15
dmnall Registered User Join Date: Apr 2001 Location: Goleta, CA Posts: 505	Well I am thinking of trying to get a BW T56 or even Zexel T56(Same as BW but made by Texel), out of either a F-body or Vette.. Damn I just need to get a hold of the guy that goes around to all the shops in my area and he sells the tranny cores for $ 50 and the last one I saw from the guy just blew the syncros and lost 3rd gear... If I can get one w/ that just needs to be rebuilt, then I would be ecstatic especially w/ 5th gear being like .76 and 6th gear .50, add 4.10s and Damn you have one fast as hell truck that cruises at around 2000 rpms @ 80 Mph.. I can live w/ that, better then having 3.73 gears w/ TH400 tranny and spinning 3500 RPMs @ 80... __________________ 1968 C10 Truck LWB Fleetside 1968 C10 Truck SWB Stepside 1994 K2500 Ext Cab Fleetside 2008 Honda Civic Si lease

03-24-2003, 11:14 AM	#16
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,521	http://www.rverscorner.com/info/auxtrans.html thats a good review on the 2 most common aux tranys. i always want to know the down side to everything im looking at getting. this guy does a great job giving you the no b/s view of them.. i love stuff like this! has any one on the board delt with these on our trucks? oh , and im glad to see i am not the only one who doesnt like the 700r4. i have been feeling like the loan ranger here for a while... __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban Last edited by mtdave2; 03-24-2003 at 11:18 AM.



Register or Log In To remove these advertisements.

03-24-2003, 12:18 PM	#17
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	i'm running a 2004R that's been built up alot easier to install just move the crossmember and bolt it in no driveshaft mods needed so far i have 30thousand miles with no problems __________________ 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

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Register or Log In To remove these advertisements.