700 TV Cable malfunction

[LTZ C20]

Hey all. I have an issue with my trans tv cable. Getting frustrated and need some fresh eyes and ideas.

Have new engine and trans in my truck. Hooked up the TV cable, adjusted,  drove a few times, no more than 2 miles per drive. Trans wasn't shifting right (to early of 1-2 shift, holds 3rd to long, 3-4 shift not as firm as it should be). I discovered my TV cable was stretched from time and use. Got a new cable, hooked it up, shifting a little better but not enough to be progress.

I have a small extension arm off the carb linkage (holley 600) it's about 3 inches long. Made it so when the OLD cable was pulled just taught, the extension would connect the cable to the carb link. But it had a droop and was loose.

Now the NEW cable is obviously shorter, so I attached it the extension, holds taught and straight. When the cable is adjusted, now the cable has slack in it and when at idle position has a droop and doesn't return to taught and straight.

So I drilled another hole in the extension,  behind the first hole, thus moving the attaching point forward towards the grille. When attached is taught, adjusted cable again,  has another droop!

I made the extension with a small piece of bar steel. All the ones I found online, such as summit, are basically aluminum, cut into a "billet design" and painted various pretty colors. I figured why spend money on something I don't like the look of, so I made one.

Now when the carb link is rotated as if you are accelerating, the cable is pulled down and then forward. The extension is acting as a type of lever, transfering the cables movement to down or up when it should be straight forward and back.

I'm having trouble now because I can't figure out how to make the TV cables movement be the proper forward and back and stay taught at idle, adjust properly and in turn make the plunger in the trans give proper fluid pressure making it shift right depending on throttle input. I'm quiet frustrated now lol. All I want it for it to work right so I can drive it to the gas station, exhuast shop, driveline shop and then drive her as my DD again and stop driving this silly tahoe. Haha.

Ideas?

Additional info if needed:
-intake is EdelB Performer RPM dual plane
-engine is 355 SBC
-engine is brand new, having about 800 miles on, trans is brand new, having about 10 miles on.
-throttle cable appears to be opening to Wide Open Throttle as it should

[LTZ C20]

Snapped some pics this morning.

The sag:


Adjuster close up:


Extension bar:


Overall wide view:

[BADAZ chevy guy]

First off, Get the right bracket before you burn the transmission up. This gives you the correct geometry. Second, the cable needs to be level with the throttle. Looks like yours is lower because of the highrise manifold. You'll need to raise the cable attaching bracket behind the carb.

[LTZ C20]

Oh ok I see how you mean for raising the manifold bracket. I'll have to look for something or build somethings that does that.  Does it need to be side-by-side with the throttle cable?

The bracket you showed a picture of, I'm guessing Summit or some place like O'Reilly's should have it if they have a performance section?

How does that bracket attach?

[LTZ C20]

Hey guys, so I ordered this bracket from O'Reilly auto.


That should bring my cables together where they are supposed to be. At least according to Summit it should. Got it from O'Reilly's, be here tomorrow, summit took to long lol. Gotta fix it so I can go to the gas station.

II a ready have the little T bolt that the cable hooks too. That will go directly on the carb and together should be correct.

[BADAZ chevy guy]

Between the bracket and the carb adapter, you should be okay. Once you have them installed, do an adjustment and let us know if it's working.

[LTZ C20]

I will not be using the carb adapter. I looked up that part on summit racing, it says it doesn't work on carbs with a factory installed ford kickdown. My carb is pretty universal so it has that kickdowm, however it also has that lowest hole on the throttle linkage which summit says should be where to attach my T post.

So I will attach the T post and the bracket this weekend.  Then I'll drive it and post my results.

[Irish_Alley]

just curious but couldnt you take that stud out of the intake and move your tv cable bracket to the same hole as the throttle but turn it upside down and run a bolt into the intake?

[LTZ C20]

Irish, I wish you could have seen the look of relazation on my face as I read your post. I could feel this sense of embarrassment. Lol

To answer your question tho. Yes I probably could have. The throttle bracket is to large and out standing however. And the TV bracket would require some bending and tweeking. I would rather just get a one piece bracket that doesn't look silly.

Thanks for the insight tho.

[Irish_Alley]

lol dont know when you will get your new part but at least you could drive the truck now.

[LTZ C20]

It will be here today, however I can't pick it up till tomorrow.

[LTZ C20]

Hey guys. I got that bracket put in today. Adjusted the cable. I also put in a new battery. Anyway, all hooked up, looks better than my ugly brackets, she drives very good. Total change from what it was doin. Now it shifts great, solid and firm when you step on it. Working perfectly now!

I need to get exhuast and a new driveline for it. Other than that trucks pretty much ready to be my DD again. Thanks all for your help again.

[HAULIN IT]

LT, All I'm going to say is...If you didn't kill the transmission with THAT mess, you are one lucky guy! The geometry with that extension sooooo far off it's not funny, not to mention unless it had something I'm not seeing...could be moving around on the one bolt pivot! Lorne

[LTZ C20]

Yea haha. Like I said tho, trans is brand new and only had like maybe 10 miles on it. I didn't drive it until I was happy with the shifting. Now that it's good, I'm gonna register it and make appointments for the exhuast and driveline to be done.

I'm sooooo done with the tahoe, miss that truck so much. It's been about a year since my old engine started failing. A year later, just about the whole power train has been replaced and upgraded,  plus other bits and pieces.