GM TBI System and TH350/700R4 Transmissions

After spending way too much time in parts books, I have come the conclusion that there were no GM trucks built with throttle body fuel injection that used the TH350 or 400 automatic transmissions. They all used the 700R4. This poses a problem when it comes to installing a TBI system with these transmissions as it relates to the kick-down or detent cable. A detent cable housing from a truck with the 350 tranny isn't quite long enough to reach the upper bracket used with the TBI and, in fact, the cable isn't quite long enough either - by a couple of inches. A TV (throttle valve) cable from a TBI truck is the right length but the end that hooks to the carb/TBI won't function properly with the TH350/400. A delemma indeed.....

I visited my local auto parts store and the man behind the counter came up with a universal cable. It's actually pretty slick. The length of the housing is adjustable from 21" to about 35". You need about 32" for this application. The cable itself is also adjustable and it comes with ends for the 700R4 as well as one for the TH350.


Here's the universal cable laying next to the TH 350 cable. The universal cable is manufactured by Automatic Transmission Parts, Inc and carries part number Y-754. It cost around $25 (2007).

Here's what the carb/TBI end of the cable looks like. You can see it comes complete with an end for the 700R4 transmission when being used as TV cable - it's the little black tear drop-shaped piece - and an end for the TH 350 when used as a detent - the metal piece with the slot in it. The little brass barrel with the screw in it allows you to cut the cable to any length you need and lock it down.
This is where the upper part of the housing telescopes into the lower part. You slip the upper housing in or out to get the length you need and tighten the fitting which keeps the two halves from sliding.
The transmission end of the cable is just like stock and works on either type of transmission.