Body alignment measurements question

[BFM_Cuda]

Am I reading this chart correctly?

From the "O" line, is it 2.75" to the bottom of the frame rail, and 8" to the center of the spring perch?


Looking at the chart and car, the difference between the two measurements is 5.25", but the perch isn't that high above the frame rail bottom. So, i'm a little confused..
1971 barracuda/challenger show the same numbers in the red circle.

[Cuda Cody]

I don't think the 8" is taken from the 2.75"?  See the 5"?  Where is it taken from?

[RJChallenger]

That's not an 8,  as in 8" The letter E and F as well as the #8 could be reference points. the drawing says from the center of the frame bushing hole to the body center line is 2.75". You need to see if there's a chart on one of the pages that tell you what the E&F as well as the #'s mean ,ie view from this angle or maybe an exploded view of that part.

[BFM_Cuda]

I don't think the 8" is taken from the 2.75"?  See the 5"?  Where is it taken from?

I guess what I am asking is, "what are the two points being measured at 2.75"? From the "O" line to what? "

I believe the "O" line to the spring perch center is 8".

[RJChallenger]

All dimensions given are to decimal points ie .75 or three quarters of an inch , 56.88 or fifty-six and seven eights. That 8 is meaningless in the equation.