What is the correct 700R4 TV cable bracket geometry?
The TV cable pin center belongs about 1 3/32 inches from the throttle-shaft center, with roughly 33% of lever travel behind the shaft centerline at idle (about 1/2 inch) and 67% ahead at wide-open throttle (about 1 inch). That rising-rate pull is what makes line pressure jump quickly off idle and flatten at heavy throttle; the cable end must stay between 1 7/64 and 1 1/8 inches from the shaft and sweep a 78-degree arc. If your carb or throttle body lacks the right hole, bolt on a geometry corrector: Holley 20-121 for Holley carbs, Edelbrock 8026 for Edelbrock/Carter carbs, or an Edelbrock 8018 stud welded to the lever.
Last updated
Who this applies to
- Computers: none - hydraulic control
- Engines: small-block Chevy, big-block Chevy, LS with carb/EFI running a 700R4
- Transmissions: 700R4, 4L60 (non-electronic), 200-4R
- Not for: 4L60E/4L80E - no TV cable
Holley 4150/4160 carburetor
- Bolt the Holley 20-121 kickdown lever to the throttle lever; it corrects the geometry for throttle valve cables.
- Use it with a kickdown/throttle cable bracket such as Holley 20-95 (steel) or 20-112/20-119 (aluminum). matching bracket
- Set the adjuster mounting point at the measured WOT cable-stop distance plus 3/16 inch. WOT stop + 3/16 in
Edelbrock/Carter AFB carburetor
- Use an Edelbrock 8018 kickdown stud (or a junkyard GM button) welded to the throttle lever at the measured location.
EFI throttle body or other induction
- Fabricate the bracket to TCI Figure 2: cable end 1 7/64 to 1 1/8 in from the throttle shaft, sweeping a 78-degree arc closed-to-WOT. 1 7/64-1 1/8 in; 78 deg
- Verify with a pressure gauge that pressure rises fast off idle and slower at heavy throttle; an even pull means the geometry is wrong. gauge check
Careful
- Wrong geometry means low pressure at light throttle, which burns the 3-4 clutch pack - verify with a gauge, not by feel.
- TH350 kickdown brackets look close but the geometry is wrong; transmission failure can result.
Go deeper
Check this first
- Measure pin center to throttle-shaft center: about 1 3/32 in.
- Check lever position: ~1/2 in behind the shaft centerline at idle, ~1 in ahead at WOT.
- Gauge-check line pressure: it must rise fast off idle and slower at heavy throttle; an even pull means wrong geometry.
Try this, then this
- Weld an Edelbrock 8018 stud (or junkyard GM button) to the lever at the measured spot. — Gives the correct 1 3/32-in radius when no bolt-on exists. Worked if: Geometry measures to spec.
- Fabricate a bracket to TCI Figure 2 dimensions and verify with a pressure gauge. — Last resort for odd throttle bodies; the gauge proves the geometry. Worked if: Pressure curve matches the fast-off-idle spec.
How you know it's fixed
- Cable end stays 1 7/64-1 1/8 in from the shaft through a 78-degree arc
- Line pressure jumps quickly off idle on the gauge
- Shifts land in the TCI mph ranges with no soft stacking
Key numbers
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| What | Value |
|---|---|
| Cable pin radius from throttle shaft | approximately 1 3/32 inches |
| Lever travel split | ~33% behind centerline at idle, ~67% ahead at WOT |
| Lever travel in inches | about 1/2 inch rear at idle, 1 inch front at WOT |
| Pressure-rise characteristic | fast off idle, slower at heavy throttle |
| Cable-end distance from shaft | between 1 7/64 and 1 1/8 inches |
| Cable-end arc | 78 degrees from closed throttle to WOT |
| Adjuster mounting point | measured WOT cable-stop distance plus 3/16 inch |
| TCI-listed cable button | Edelbrock 8018 or junkyard GM button |
| TCI-listed correction kits | Holley 20-121; Edelbrock 8026 |
| Holley 20-121 function | corrects TV cable geometry on Holley 4150/4160 |
| TCI brackets by carb | 376700 for QJet/Carter/Edelbrock; 376800 for Holley |
Every option we know of
| Maker / product | Part # | Fits | Price | Where | Status / notes |
|---|---|---|---|---|---|
| Holley 700R4 kickdown throttle bracket | 20-121 | Holley 4150/4160 carbs with 700R4 | Buy Summit Racing, Jegs, Chevelle Depot | In production Use with Holley 20-95/20-112/20-119 cable brackets. | |
| Edelbrock TV cable geometry corrector | 8026 | Edelbrock/Carter carbs with 200-4R/700R4/4L60 | Buy Summit Racing, Jegs, LMPerformance | In production Edelbrock and Carter carburetors only. | |
| Edelbrock GM trans kickdown stud | 8018 | 200-4R/700R4/TH350 throttle levers | Buy Milky Motorsports and others | In production | |
| TCI Automotive TV cable bracket | 376700 | Rochester Quadrajet, Carter AFB, Edelbrock Performer | Buy TCI Automotive, Summit Racing | In production | |
| Bowtie Overdrives TV cable kit | 700R4 swaps | Bowtie Overdrives | Mentioned by swappers; confirm contents for your induction. |
Prices are approximate as of September 2026. We list every option we know of, including small shops and used parts we can't link to. Confirm fitment with the seller.