This is a followup for CBenson, about the Holley Throttle lever and the TV cable adaptor.
What you see here is the adaptor that Holley offers to attach to the Throttle lever to accept the TV Cable. This particular version is bolted to a Holley 650 Spread Bore that came off my 85 Monte Carlo back when it ran a TH200R4. It is attached to the basic throttle lever using two bolts. As the picture shows, one does dual duty as it has the mushroom shaped tit that the TV cable end fits over. The other is either a 1/4 or 5/16 grade 5 capscrew that I machined the head down on to gain clearance for the cable to move past without binding or hanging up. That was just a few minutes work on a lathe or you can go tribal and do it with a 4.5 angle grinder and a flapwheel.
For the sake of comparison, this is a picture of the throttle lever from my 600 Cathedral Bowl Centre Float Holley. Note that the Throttle lever for this carb does not offer the same mounting point for the adapter as the 650 did. At the very bottom of the throttle lever there is the ear to which the return springs hook up and immediately above and ahead of that there is another tab that has been drilled. This would be the probable mounting point for that bolt with the mushroom head on it that is pictured above. That part has a part number and should be in the Holley parts catalogue.
For the keen eyed readers among you, my description of this carb is not incorrect. But, you dispute, Holley never made a Cathedral Bowl, or center float version of the 600 CFM. So What?? To paraphrase a classic, they may not have, but I did. The conversion is not difficult and the parts are, you guessed it, in the catalogue, or you can hit a swap meet or go on line or find someone with a stash and do some shopping. The conversion made it a lot easier to drop the bowls and swap jets and do other tweaks. To make life simpler along the way, I used Moroso bowl gaskets and opened up the feed holes using a gasket punch, along with their nylon bowl bolt washers that can get re-used almost forever. I did go with the early slotted head bowl screws to begin with but found the later hex-head ones to be easier to work with and torque down correctly.
If nothing else the look does make people do a double take, or would have if it had been somewhere they could see it; as it was this carb was the one I ran on my other "G" model, that being my Chev G10 Van!. Finally bit the bullet and swapped it out for an FI. Why? Mostly because to make and keep Holley's doing what they do best, you have to keep after them. They are fickle mistresses and hate both humidity and changes in barometric pressure, all of which means they are better suited for life in Arizona as opposed to Louisiana or Florida. In a car with a hood to pop, doing the incessant tuning would have been a little easier to pursue. The van required that I take a large chunk of the dash apart and pull the doghouse to gain access. I actually ran with the house off a few time during one tuning run just to be able to get immediate access for tweaks. All kinds of fun sitting beside a small block with nothing between you and it except a smile!
Anyway, CBenson, hope this finally offers you the details you were looking for. For setting up the cable tension, as I commented elsewhere, find a manual. it is not complicated but has to be done right or you could lose the t-mission to internal suicide.
Nick