From a forbodiesonly post
"Heavy duty suspension with sway bar. C is for suspension. 4 is for code 624 which is the above. Does this match up to your car"
I know the below info is from 67 but some info is the same for 68
My 67 dart has the "rally suspension" package it has front KH disk, sway bar, 892/893 tortion bars, 6 leaf rear springs, heavy duty ball joints. And it's only a 273 2bbl.
The build sheet lists many codes for suspension components in verious places. This one aligns with the post from B bodies only.
Except the code heading says "WO. S. BAR"
View attachment 1716014011
