#3992592
Apparently used on various GM until 1972, based on other reports.
It is listed in Firebird parts manuals and the 2nd gen diagrams in 1972 and 1976. The 1980 Assembly manual that uses the same diagram has it removed. It does fit, it's a neat detail, but it doesn't do much. You need a lot of adjustment slack and bad luck to be replacing cable under the car and somehow push it back and out the slot.
Way back, maybe 2 years ago, I posted on a forum somewhere (I did quick search and didn't find it) that I'd obtained a rusty original of this, having never known of such an animal. Within a few weeks the reproduction appeared and my grand discovery lessened! I have that also, tested only. I thought it may be slightly more useful on mine since being a modified setup, has limited access to that side of the park brake assembly against the other kick panel. Good for holding it in place, bad for wanting to change cables. But that requires more work anyway beyond flicking a clip off.
It still appears in the 76-81 Parts Manual diagram as #20, but not the parts listing. Still just reusing diagrams from previous years, albeit with revised cable setup for 75-81.
https://live.staticflickr.com/65535/51356370593_64438b00fd_b.jpg
