/6 K-Frame vs. V8 K
None of the suspension routes through the K-frame on the 72 back. All suspension is the same on the 68 to 72 K-frames. 1967 is the same except the idler arm and that part is a one year part. The sway bar routes through the K-frame 0n the 73 up. In other words the 73 up sway bar set up will only work if you cut the earlier K-frame.
It is said the 340 K-frame is better constructed than the regular V8 frame and has rear supports. The 340 K-frame can be identified by the washer that is welded on it.