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700 R4 speedometer in old Chevy

  
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700 R4 speedometer in old Chevy

 
supersport66 supersport66
New User | Posts: 49 | Joined: 01/08
Posted: 11/21/12
07:20 PM

How do you get old cable speedo to work with new electronic sending unit.
I have a 66 Chevelle has T350 trans now was thinking of getting 700R4 for better gas milage and wondered how that works.
B.A. in Fla.  

waynep71222 waynep71222
Enthusiast | Posts: 448 | Joined: 03/12
Posted: 11/21/12
09:56 PM

there are several ways to solve this issue..

there are mechanical speedo cable conversion kits...

there are Tachograph motors to drive the speedo head.... using the speedo output..

if you pull the speedo housing out of the side of the 700R4.. some actually are GEAR Driven... so you can just exchange the speedo housing for one of 2 different speedo housings to drive a speedo cable..

there is a slight difference in where the driven gear is centered in the speedo housing...

if you get into the Later 4L60 and 4L60E transmissions... most of those have reluctors on the output shaft and magnetic pickups to count the pulses..  without the use of plastic speedo gears..

so it really depends on what year you donor transmission is...

the tachograph motors that drive the speedometer heads are rather expensive..

there may be more than one way to do them..  

supersport66 supersport66
New User | Posts: 49 | Joined: 01/08
Posted: 11/22/12
06:30 PM

Thanks Wayne I was thinking about getting a 700R4 from Summit Racing.Do you think they have a adapter to make it work on my Chevelle?  

zman123 zman123
Enthusiast | Posts: 531 | Joined: 06/08
Posted: 11/22/12
11:46 PM

I had a 700R4 put inb both my 69 malibu and 77 4x4 truck  and the transmission shop put in the adaptor, it looks pretty simple, both work well nothing was noted on the bill for either vehicle so I assume they were not that expensive.  

waynep71222 waynep71222
Enthusiast | Posts: 448 | Joined: 03/12
Posted: 11/23/12
01:42 AM

wow.. i usually handle that locally at the local transmission parts wholesaler..  the store that sells parts to transmission rebuilders...

give them your gear ratio...  they will need that to select your proper set of speedometer gears and supply the proper speedo gear housing...

i have not dealt with summit on this area... so i will have to do some research..  

waynep71222 waynep71222
Enthusiast | Posts: 448 | Joined: 03/12
Posted: 11/23/12
01:55 AM

don't forget that with a 700r4.. a 200 4R... with throttle valve cables.. that you need an adaptor arm for almost any carb throttle lever to get the PROPER throttle lever position to amount of PULL..

failure to install and properly adjust the throttle valve lever adaptor will result in a VERY SHORT transmission life... i am Talking BLOCKS... before its burned out.. oh.. and if you don't show that you purchased this cheep adaptor.. they will probably NOT warrantee the transmission..

a very long time ago. thinking about warrantees.. i was building a fairly warm pontiac motor for somebody i knew..  on the way back from where we dropped off the block and crank for machine work... as i was going to do the triple checking everything and assembly.. he ask how long i was going to warrantee the motor for... 12,000 miles.. 24,000 miles..   i looked at him as said.. to the end of your driveway is all you get...  so he decided on somebody else...  no shirt off my back as i was really busy on other projects... when it was done.. built by the other guy.. he took it out and did a massive burn out on the first trip out the driveway.. must of had the motor going 8000 rpms...  i drove past when i heard about it.. found the pair of stripes from the rear tires.. then the puddle of oil..  he did ask if i would fix it.. i passed..