Throttle linkage breaking over and over again.

Is it stretching or going through some strange bends? How exactly do you have it mounted?

I found an adjustable bar linkage from the local speedshop for under $20. Hooks up to the stock pedal arm by the firewall and has bushings for a Holley carb throttle arm.

The easiest guess is that you are using the 2 barrel throttle bracket on the 4 barrel setup. The brackets are different and not interchangable. I almost made that mistake but I don't think the throttle would close all the way with the 2 barrel bracket... If that is not the problem, here are some other suggestions I posted earlier...

If the cable is breaking, I wonder if there is too much slack in it to start with. Unhook the ball and socket from the carb and then have someone floor the gas pedal while you hold the carb all the way open. Tug on the cable. If there is more than ~1/4 between the socket on the cable and the ball connection on the carb, that's probably the cause. Is the cable breaking at the firewall, the pedal or the carb end? Did it break under hard acceleration? If you have a geometry issue (cable to short), you can make your own bracket.
I made my own bracket to save money. I bought a stock 4 barrel bracket from NPD (converted from 2 barrel when I rebuilt engine) and used it as a pattern to make a bracket. The only really critical dimmension is the distance from the rear carb bolts to the face of the bracket where the square cable head comes through. Make sure that the throttle will open and close all the way. I used a 1/4" bar of steel and then welded an angle iron on the back edge. I placed the holes in the bar such that the cable head was the right distance from the throttle (to get full actuation). I left a small bit of the angle iron extend downward so that I could put the return spring on it. I trimmed it down and painted it so it actually looks nice. Due to the thickness of the bar, I had to get a set of longer carb studs for the rear. So far it works great. When I was done making my bracket I returned the $50 stamped bracket to NPD...

Sorry I don't remember. It's been years and as far as I know it was a generic item carried by the shop.

The 4 barrel bracket has the carb attachments almost inline with the square hole that the cable comes through. The square hole is just slightly rearward. The 2 barrel carb bracket has the carb holes significantly forward of the square cable hole.
I am not familiar with the Holley carb either.. the Edelbrock (Carter) I have has the throttle cable attachment in the same place as on the stock carb.

Is the cable frayed or just snapped off? Is it broken right where it attaches to the pedal bracket?

BrownPSU78 said:

it looks like it frayed until the point of snapping.
--Brown

Click to expand...

Is the pedal chafing through the cable? Take the pedal out I'd bet its sharp enough to eat the cable. Hit it with a dremmel and put it back together with a new cable, find a piece of heat shrink tube to go over the cable after you have filed the pedal and it shouldnt break again