Thinking about replacing th350 with 700r4 - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 10 (permalink) Old Jan 12th, 10, 11:25 AM Thread Starter
Lifetime Premium Member
Lance
 
Join Date: Sep 2008
Location: Groton, CT
Posts: 572
Thinking about replacing th350 with 700r4

I have a slightly modified 383 stroker and behind it is sitting a hughes th350 with a b&M floor shifter and although I like the way the setup is... I am pretty upset that I cannot drive on the highway well or to any shows or even to work well because the RPM's are screaming! So I am looking at the 700r4 but with this I have Q's for my setup.

1) Will I have to figure out a new driveshaft or are the two transmissions the same on the outside?

2) With this transmission will I have to look at getting some sort of lockup control thing?

3) The TV cable am I understanding correctly I cannot use my current cable? Its a new one from Lokar that is currently hooked up to my 750CFM Summit Carb....

4) Would the stock setup of a 700r4 stand up to my stroker if I am never dragging in it at most just normal romp for a burnout on occasion or stop light gunning?

Thanks a bunch
steinklatre is online now  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old Jan 12th, 10, 11:44 AM
Senior Tech Team
kevin
 
Join Date: Sep 2008
Location: Smiths Station, Alabama
Posts: 2,217
Re: Thinking about replacing th350 with 700r4

fwiw....I put one in my 67ss last year. I had a real top shelf local builder assemble it using all of his tricks. it is living fine behind my new 496/600hp motor. you will have to shorten the driveshaft, ect...there are numerous posts on here so I wont go overboard but as far as lock-up, I just use a double post brake light switch and run a positive charge to the 4th gear solenoid (per my builders recommendation). it switches the lock-up off when you press the brakes. I use a lokar cable (per my builders recommendation). it allows micro adjustments. not sure if the th350 would work but I doubt it. you will need an adapter to the carb to hook up the cable for proper geometry (bought mine from pheonix transmission)...
the low gear of the 700r4 is awesome. I run a 3.42 rear gear with 26.1 tall tires all around. on the hi-way it is running 70mph turning about 2200 rpm......do a little research and dont forget local guys. my whole setup including a new driveshaft set me back $1800..
look for a trans from around 1991 too as I was told it was the best....monster transmission has some great info on its website too..
the heckler is offline  
post #3 of 10 (permalink) Old Jan 12th, 10, 11:49 AM Thread Starter
Lifetime Premium Member
Lance
 
Join Date: Sep 2008
Location: Groton, CT
Posts: 572
Re: Thinking about replacing th350 with 700r4

Quote:
Originally Posted by the heckler View Post
fwiw....I put one in my 67ss last year. I had a real top shelf local builder assemble it using all of his tricks. it is living fine behind my new 496/600hp motor. you will have to shorten the driveshaft, ect...there are numerous posts on here so I wont go overboard but as far as lock-up, I just use a double post brake light switch and run a positive charge to the 4th gear solenoid (per my builders recommendation). it switches the lock-up off when you press the brakes. I use a lokar cable (per my builders recommendation). it allows micro adjustments. not sure if the th350 would work but I doubt it. you will need an adapter to the carb to hook up the cable for proper geometry (bought mine from pheonix transmission)...
the low gear of the 700r4 is awesome. I run a 3.42 rear gear with 26.1 tall tires all around. on the hi-way it is running 70mph turning about 2200 rpm......do a little research and dont forget local guys. my whole setup including a new driveshaft set me back $1800..
look for a trans from around 1991 too as I was told it was the best....monster transmission has some great info on its website too..
Great info what all goes into this shortening of the driveshaft? Any sort of place in particular I would/should take it to? I understand on the cable... not too big a deal what most concerns me is the swith thing how is it to the 4th gear? I just can picture it. Is it simpler than I am realizing?
steinklatre is online now  
 
post #4 of 10 (permalink) Old Jan 12th, 10, 12:52 PM
Lifetime Premium Member
Chris
 
Join Date: Oct 2005
Location: Wichita Falls,TEXAS
Posts: 3,234
Garage
Cool Re: Thinking about replacing th350 with 700r4

I have been running a Phoenix Transmissions 700R4 in my El Camino with a 383 stroker with sucess for a while now. Give them a call. They will be more than happy to talk to you about your questions. Ask for Greg or Scott.

http://www.phoenixtrans.com/

To answer your questions. You will have to cut 2.75" inches from your stock driveshaft. Any drive line shop can do it for $100 or less with a rebalance. The cross member will have to modified to fit the new mount.

When you order your parts make sure you get a new dip stick, TV cable and TV cable bracket. Also make sure your cooling system is up to par. Heat kills trannys.

Good Luck

1967 Chevelle 496BB/TH400/Strange S-60 (Show and Go)
1967 El Camino 388SB/700R4/12-bolt posi (Rat Muscle Parts Hauler)
2015 Harley Davidson Road Glide Special (Cruiser)
2018 Chevy Silverado LTZ Duramax (Daily Driver)



My Chevelle: https://www.chevelles.com/feature/nov98.html


C & D Performance

North Texas Chevelles
Motorhead62 is offline  
post #5 of 10 (permalink) Old Jan 12th, 10, 1:39 PM
Senior Tech Team
kevin
 
Join Date: Sep 2008
Location: Smiths Station, Alabama
Posts: 2,217
Re: Thinking about replacing th350 with 700r4

thanks lance. in fourth gear it is something like 30% less rpm than the th350 1:1 ratio (my car came with a pg)...in 4th the 700r4 trans "lock-up" and is pretty much is like a fix "in" gear deal (I think). supposed to help with gas mileage was the idea (I think). if it did not not "unlock when I pressed the brake (power-off to solenoid temporarily) it would not let the converter slip (I think) and would lug the engine down. not to mention be very hard to stop at an intersection. as I mentioned before - I am no expert - go to the monster, bowtie overdrives, pheonix and this website and do some research. one note about cutting that drive shaft - I recommend measuring the distance once the trans is in the car and the car fully supported on its wheels. these old cars were not computer generated like the new ones and some things varied. (like how my june '67 build supersport has '68 length 12 bolt housing/axles from the factory) and although the great information will lead you to just shorten it, be realistic and measure (several times) before you cut it. since my car has over 627 ft/lb of torque at the crank - I chose to get a new driveshaft built out of some dom tubing with hd u-joints by wiles driveshaft out of tn. they do a lot of dirt circle track cars work around here. plus I still have my original motor and trans if I ever sell it to make it back in to a "numbers" car.....go for it !! you will be happy with the low gear and o.d.......
the heckler is offline  
post #6 of 10 (permalink) Old Jan 12th, 10, 6:23 PM
Tech Team
 
Join Date: Oct 2005
Location: Hammonton, NJ
Posts: 126
Smile Re: Thinking about replacing th350 with 700r4

I have a 2004r from Monster trans, love it. 388 with 425 hp 4.11 12 bolt posi with 275-60-15 tires. 2500 stall lockup converter, cooler. About 17 mpg, mid 13's quarter with street tires 104mph trap speed. No cutting of driveshaft, bolts right in, cost me on a special $1800, supposed to be rated to 450hp. I can smoke the tires at any speed. Tranny came from a buick grand national as per the serial number. Better tha the 12 mpg I was getting form the turbo 350 which I had blown up. Do it, you will not be sorry when you drive by the pumps and wave!
ewscott is offline  
post #7 of 10 (permalink) Old Jan 13th, 10, 10:16 AM Thread Starter
Lifetime Premium Member
Lance
 
Join Date: Sep 2008
Location: Groton, CT
Posts: 572
Re: Thinking about replacing th350 with 700r4

Alrighty spoke with the boss "wife" and shes for it but for monetary reasons wants me to sell that new Hughes th350 to get money back! Booo but hey its life! So I am going to go with

-B&M 70248 Converter Lock-Up Control(its more but so simple)
-Driveshaft is going to be cut (after trans is in) by a local company for $75.00
-Not sure on which converter yet but thinking 2K-2,5K??
-TV cable kit from phoenixtrans for $154 yet again so easy
-Trans is a rebuilt from a local shop for $550 I am not worried about racing built yet if it busts ill upgrade....
steinklatre is online now  
post #8 of 10 (permalink) Old Jan 13th, 10, 1:44 PM
Lifetime Premium Member
Bob
 
Join Date: Mar 2005
Location: Jeannette Pa. near pittsburgh
Posts: 8,233
Re: Thinking about replacing th350 with 700r4

I have a 1970 Nomad Sta. Wgn. 307-2V engine with a 350-T tranny. If you have a GOOD 700R4. Here is what you DO NOT need to buy.
1-- My 350 tranny cooler lines bolted up to my 700
2-- Move the crossmember back, and bolt in the 700
3-- look on your old engine for the piece with the 5/8" square hole. This is the same size hole as the 700 TV cable,
4-- Get a small machine screw 8/32-10/32 whatever. Grind the O.D. to match, Then grind off the sloted part to match the width. Then drill a matching hole in your carb-- 1 and 1/8" from the centerline of the butterflys at 58 degrees to the rear. This is a static adjustment.
buy a dual pattern flex plate from summit 60-80 dollars(700s have a small pattern
5-- Take the " U " shaped shifter from your 350-T and bolt it on the 700 and re-connect your stock shifter
6-- My seven year old lock up kit still works fine, It cost $99.00 shipped to you house. Run a 12-Vt. Ign/on with an inline fuse and plug in to the 700 plug on the tranny, This is an Elect. loc-up. No magic involved.
7-- I did add an extra cooler or I am running two coolers
8-- Most of the parts you need except-Drive Shaft getting cut// Flex plate & loc-up
are in your garage. The stock 700 (Red ) dip stick bolts to the bellhousing just like the 350-T.
9-- Where did I get all this information???? I went to a junk yard and looked at a V-6 or a V-8 Chevy with a 700R4 and got out the yardstick and copy down some numbers. NOTE: For the rear mount for the TV cable, To make it look real stock, Find an old chevy P/U with a Q-jet and a 400-T. Look on the back of the Q-Jet. Take out the back two bolts and WA-la You now have a bracket for the TV cable and it is in the correct location.
My I.Q. is about 3 points above an orange traffic cone. My 700R4 has been working fine for 8 years now. I have a 3:07 12 bolt in my Red 70 SS 468 wagon . on the interstate at 72-75 MPH the 468 is turning 1950 RPMs and 19.7 MPG. Now I added a electronic servo cruise control, Just to give my foot a rest. My wagon is on its second set of tires, 3rd B.B. and the same 700R4. Good Luck and Git-er-done
Bob If I can help in any way just ask......................ACES--AACA
Click on the blue to view my two..............

1970 SS LS-5/M-22 El Camino- Org. Owner-AACA 2016-Senior Grand National Winner---MCACN-GOLD-2013
1970 ( FRAUD) SS 468 Station Wagon - Driver.
Robinls5 is offline  
post #9 of 10 (permalink) Old Jan 13th, 10, 1:59 PM
Senior Tech Team
kevin
 
Join Date: Sep 2008
Location: Smiths Station, Alabama
Posts: 2,217
Re: Thinking about replacing th350 with 700r4

your cars are top notch bob.....I must do an elco next !!! that wagon is way cool too.....

I too think lance will be very pleased with a properly built 700r4.
btw...my motor runs a pretty aggressive cam. my builder recommended a "corvette" 12" torque converter. cost $99 locally. it has a 2075 rpm stall rating behind a small block. feels like about 2200-2400 behind my 496....works great....
the heckler is offline  
post #10 of 10 (permalink) Old Jan 13th, 10, 6:58 PM
Gold Founding Member
Ron
 
Join Date: Aug 1998
Location: Murfreesboro,Tn. USA
Posts: 5,713
Re: Thinking about replacing th350 with 700r4

Get this bracket, cheap insurance to know you have the correct geometry.
http://www.summitracing.com/parts/HLY-20-121/
Ron

70 Chevelle SS396 (496) Straub roller, 700r4
69 Malibu convertible (sold)
95 Z28 Convertible T56 6 speed
TC #54 Gold


70 side
On Gearz
ToocoolZ28 is offline  
Sponsored Links
Advertisement
 
Reply

Tags
700r4 , th350 , transmission swap

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 3443 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome