Whats involved? - 700R4 in, TH350 out - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69C10@16 · 01-31-2008, 01:28 PM

Helped a friend swap a 700r4 out of his 91 camaro this weekend and he gave me two old 700r4s. The one that just came out of the car was slow to shift and felt like it was slipping. The other one 'supposedly' would not upshift correctly. If I rebuilt one of these things, what would be involved in putting it in? I figured on buying a Lokar Auto Trans Floor Shifter for it so linkage ont he column isnt going to be an issue. I think what I was worried about the most is the crossmember. Will a 700r4 bolt straight in where the turbo 350 was? Oh, and does anybody have a link to a calculator for speedometer gears? This is by NO means going to happen soon I just wanted all my info together before I made any plans.

Longhorn Man · 01-31-2008, 01:56 PM

I hate it on other boards when someone asks a question, and the responce is "did you check the search?"
However, this is covered 3 or 4 times a month.... search will net you all the 700 R4 info you could ever need.
I'm 99% sure there's a few threads in the FAQ section too.

**tll74** · 01-31-2008, 02:09 PM

Well, I'm in the process of doing the same. I do know that you will have to shorten the driveline, move the cross member back and drill new holes, hook up the throttle valve cable to the carb, redo the wiring internally for a single wire power source controlled by a vacumn switch for lock-up. I believe that's about it. Not sure about the speedo part. I plan to try mine and correct it with a correction gear box. Exact specifications will be known soon...........

70GMCer · 01-31-2008, 09:29 PM

Here's a speedo source. It's what I used.....

http://novaresource.org/speedo.htm

ChevLoRay · 02-01-2008, 12:24 AM

You MAY NOT have to shorten the driveshaft. It all depends on the cases. With the two side-by-side, compare the length. If they're the same, the stock driveshaft should do the trick. A friend who has a transmission shop, told me that going from a TH350 to a 700R4 would keep the same driveshaft. If you change from a TH400 to a 700R4, you'll need to shorten the driveshaft.
I don't know if all 700's have the same dimensions on the case, or not.

ryan913 · 02-01-2008, 01:49 AM

That is correct on the driveshaft. If your truck has the medium tail shaft turbo 350 you will not have to change the shaft. It it is the short shaft you will have to shorten the driveshaft. Other than tv cable and wiring it is a direct bolt in. You may also have to change the carb depending on which style you have to be able to get the correct throw for the tv cabel.

69C10@16 · 02-01-2008, 01:55 AM

Im running an Edelbrock 1405 Carb so it had better work. It's brand new and I'm not replacing it. What about the wiring socket on the top driver's side of the 700r4? Is this a computer control circuit or is it just going to be a 12 volt supply line? Anybody got a diagram for it?

ryan913 · 02-01-2008, 02:26 AM

That carb will work but you may need to buy an adapter for the 700r4 tranny. Very cheap. The wiring is for the lock-up converter and for the solenoids in the valve body. There are kits available for the 700r4 for sale everywhere. Make sure you get one for your year of tranny. Hope this helps!

sparkplug553 · 02-01-2008, 04:48 AM

I made the same switch a couple of years ago....what i did was build a latching circuit and wired it in to a button on my shifter handel,then i got a brake light switch from a early to mid 90's chevrolet truck and used that to disenguage the converter as there are 2 sets of switches in one.one is always closed unless the pedel is depressed and one is always off unless the peddel is depressed.this is how i unlatched my circuit,also...as an added feature i wired in an led so i could visually see the circuit was on,not necessary,but cool none the less.

sparkplug553 · 02-01-2008, 04:50 AM

one more note.check with bowtie overdrives(google them and youll find them) they sell a tv kit that works incredibly well and have adapters for most carb's

b&a72 · 02-01-2008, 05:56 AM

Quote:

Originally Posted by sparkplug553

one more note.check with bowtie overdrives(google them and youll find them) they sell a tv kit that works incredibly well and have adapters for most carb's

I agree. I put a bowtie overdrive in my truck have not ran it yet but there TV cable kit looks very clean and easy.

**VetteVet** · 02-01-2008, 05:50 AM

Here's awebsite that pretty well covers the swap. There are other issues too, like the TV cable setup and converter lockup. There is a ton of info on the board and in google.
http://www.smokemup.com/tech/700r4.php

69C10@16 · 02-01-2008, 01:19 PM

Yeah I saw they're TV cable kit and if this happens it will be a must have. Im not gonna screw around with trying to build a bracket and all that junk, When done, its getting done RIGHT. the FIRST time. I havent found anywhere yet that tells me how to ID one of these suckers. How do I find out if they have lockup or not???

01-31-2008, 01:28 PM	#1
69C10@16 Registered User Join Date: Aug 2007 Location: Greenfield, MO Posts: 215	Whats involved? - 700R4 in, TH350 out Helped a friend swap a 700r4 out of his 91 camaro this weekend and he gave me two old 700r4s. The one that just came out of the car was slow to shift and felt like it was slipping. The other one 'supposedly' would not upshift correctly. If I rebuilt one of these things, what would be involved in putting it in? I figured on buying a Lokar Auto Trans Floor Shifter for it so linkage ont he column isnt going to be an issue. I think what I was worried about the most is the crossmember. Will a 700r4 bolt straight in where the turbo 350 was? Oh, and does anybody have a link to a calculator for speedometer gears? This is by NO means going to happen soon I just wanted all my info together before I made any plans. Last edited by 69C10@16; 01-31-2008 at 01:29 PM.

01-31-2008, 01:56 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Whats involved? - 700R4 in, TH350 out I hate it on other boards when someone asks a question, and the responce is "did you check the search?" However, this is covered 3 or 4 times a month.... search will net you all the 700 R4 info you could ever need. I'm 99% sure there's a few threads in the FAQ section too.

01-31-2008, 02:09 PM	#3
tll74 "Junkyard Dog" Join Date: Jan 2008 Location: Springfield Oregon Posts: 2,529	Re: Whats involved? - 700R4 in, TH350 out Well, I'm in the process of doing the same. I do know that you will have to shorten the driveline, move the cross member back and drill new holes, hook up the throttle valve cable to the carb, redo the wiring internally for a single wire power source controlled by a vacumn switch for lock-up. I believe that's about it. Not sure about the speedo part. I plan to try mine and correct it with a correction gear box. Exact specifications will be known soon...........

01-31-2008, 09:29 PM	#4
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Whats involved? - 700R4 in, TH350 out Here's a speedo source. It's what I used..... http://novaresource.org/speedo.htm __________________ 1997 GMC Sierra Ext 1965 Mustang

02-01-2008, 12:24 AM	#5
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Whats involved? - 700R4 in, TH350 out You MAY NOT have to shorten the driveshaft. It all depends on the cases. With the two side-by-side, compare the length. If they're the same, the stock driveshaft should do the trick. A friend who has a transmission shop, told me that going from a TH350 to a 700R4 would keep the same driveshaft. If you change from a TH400 to a 700R4, you'll need to shorten the driveshaft. I don't know if all 700's have the same dimensions on the case, or not. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

02-01-2008, 01:49 AM	#6
ryan913 Registered User Join Date: Jan 2008 Location: kenton, oh Posts: 183	Re: Whats involved? - 700R4 in, TH350 out That is correct on the driveshaft. If your truck has the medium tail shaft turbo 350 you will not have to change the shaft. It it is the short shaft you will have to shorten the driveshaft. Other than tv cable and wiring it is a direct bolt in. You may also have to change the carb depending on which style you have to be able to get the correct throw for the tv cabel. Last edited by ryan913; 02-01-2008 at 01:49 AM.

02-01-2008, 01:55 AM	#7
69C10@16 Registered User Join Date: Aug 2007 Location: Greenfield, MO Posts: 215	Re: Whats involved? - 700R4 in, TH350 out Im running an Edelbrock 1405 Carb so it had better work. It's brand new and I'm not replacing it. What about the wiring socket on the top driver's side of the 700r4? Is this a computer control circuit or is it just going to be a 12 volt supply line? Anybody got a diagram for it?

02-01-2008, 02:26 AM	#8
ryan913 Registered User Join Date: Jan 2008 Location: kenton, oh Posts: 183	Re: Whats involved? - 700R4 in, TH350 out That carb will work but you may need to buy an adapter for the 700r4 tranny. Very cheap. The wiring is for the lock-up converter and for the solenoids in the valve body. There are kits available for the 700r4 for sale everywhere. Make sure you get one for your year of tranny. Hope this helps!

02-01-2008, 04:48 AM	#9
sparkplug553 Registered User Join Date: Jan 2008 Location: San Jose,California Posts: 30	Re: Whats involved? - 700R4 in, TH350 out I made the same switch a couple of years ago....what i did was build a latching circuit and wired it in to a button on my shifter handel,then i got a brake light switch from a early to mid 90's chevrolet truck and used that to disenguage the converter as there are 2 sets of switches in one.one is always closed unless the pedel is depressed and one is always off unless the peddel is depressed.this is how i unlatched my circuit,also...as an added feature i wired in an led so i could visually see the circuit was on,not necessary,but cool none the less.

02-01-2008, 04:50 AM	#10
sparkplug553 Registered User Join Date: Jan 2008 Location: San Jose,California Posts: 30	Re: Whats involved? - 700R4 in, TH350 out one more note.check with bowtie overdrives(google them and youll find them) they sell a tv kit that works incredibly well and have adapters for most carb's

02-01-2008, 05:50 AM	#12
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Whats involved? - 700R4 in, TH350 out Here's awebsite that pretty well covers the swap. There are other issues too, like the TV cable setup and converter lockup. There is a ton of info on the board and in google. http://www.smokemup.com/tech/700r4.php __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

02-01-2008, 01:19 PM	#13
69C10@16 Registered User Join Date: Aug 2007 Location: Greenfield, MO Posts: 215	Re: Whats involved? - 700R4 in, TH350 out Yeah I saw they're TV cable kit and if this happens it will be a must have. Im not gonna screw around with trying to build a bracket and all that junk, When done, its getting done RIGHT. the FIRST time. I havent found anywhere yet that tells me how to ID one of these suckers. How do I find out if they have lockup or not???



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