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73-87 Chevy _ GMC Trucks => Interior & Equipment => Instrumentation => Topic started by: 81Cheyenne on November 19, 2008, 12:38:52 pm

Title: Electronic to Mechanical Speedo Conversion
Post by: 81Cheyenne on November 19, 2008, 12:38:52 pm

I'm changing out trannys from a 350c to a 700R4.  The 700R4 that I'm putting in is set up for an electronic speedo and looks like it has a purple drive gear.  My mechanic has found a mechanical drive housing.  I'm putting in a 3.73 rear end and will be running 29" (235/75-15) tires.  What size driven gear will I need?

Title: Re: Electronic to Mechanical Speedo Conversion
Post by: joesgarage71 on November 19, 2008, 03:20:58 pm

 This might help
http://www.2quicknovas.com/tranny.html

Or there is some good info here.
http://www.csgnetwork.com/automotiveconverters.html

Title: Re: Electronic to Mechanical Speedo Conversion
Post by: Captkaos on November 19, 2008, 04:26:48 pm

here is another one:
http://www.73-87.com/7387garage/drivetrain/speedo.htm

Title: Re: Electronic to Mechanical Speedo Conversion
Post by: 81Cheyenne on November 20, 2008, 12:52:37 pm

Quote from: Captkaos on November 19, 2008, 04:26:48 pm

here is another one:
http://www.73-87.com/7387garage/drivetrain/speedo.htm

Yep. I saw that. But did the later model 700R4's with the electronic speedo setup have a different color drive gear?  I haven't had a chance to go over to the garage to see it but my buddy said that it looked purple. 

Title: Re: Electronic to Mechanical Speedo Conversion
Post by: Captkaos on November 20, 2008, 02:20:13 pm

should use the same.