70 cuda frame dimensions ?????

[philze]

  Ok My head hurts from trying to make sense of this diagram. 
      My cuda is level off the floor with stands under the frame rails at 24 inchs. The diagram shows front rail ( line b-c) height @ 6.2 inch below body line and 5 inchs below at line d-e at the front rear spring mount. That works for me front 24+6.2=30.2, rear 25 1/4 +5=30 1/4 if line E is the lower hole.
    The part that throws me is the rear spring eye height. Were do those numbers come from? 2.75 then an 8 nothing works to my 38 1/4 . I have very little hair left to pull out on this !!!!!!!!!!!!!   
   I really want to get to welding on this but I want everything be perfect.  (well almost)
                                                                                                                              Thanks Phil

[brads70]

Hummm good questions...
I believe hole marked D OR E is the lower hole? I can't figure what the 2.75 dimension is refering to?
The other problem is I don't think the rear and front frame sections were your jackstands are are on the same plane? (the 6.2 dimension, your 24" dimension) I wonder if the 2.75 dimension is in the wrong place? Maybe it's from hole E to the bottom of the frame? Maybe try instead of your 24" dimension see if the numbers add up if you made it 24" + 2.75 = 26.75 ?

[HP2]

There is a line drawn through the wheel centerlines that projects to the rear. Based on the arrows, 2.75 should be from this line up to the bottom of the frame rail, then 8 should be from this line to either the eye or the top of the frame rail. I can't tell because of the green markings. 

[philze]

   I think I have a problem explaining this so I will try again.

 Here is a picture of the shop manual diagram.
  If I put a straight edge along the bottom of the front and rear frame rails they show to be on the same line, parallel to the body line O
 
   My frame is 24 inchs off the foor level in all directions. 
O line is shown to be 6.2 inchs above the bottom of the front frame so I have a total of 30.20 inches from the foor to line O

 O line is shown to be 5.00 inchs above point E or D on the rear spring mount. My measurement for point E is 25.25 inchs For a total of 30.25 inchs only .05 inch off. I think that is really close.

 Now for the rear spring mount:  My measurement is 38.25 inches from the floor to the center of the eye. If I am seeing this right, there is a dimension of 2.75 inches and one of 8 inches above O line. Ok I know that O line is 30.20 inches off the floor and if I add the two numbers from the drawing I come up with a total of 39.95 inches. This tells me my rear rails are 1.75 inches low !!!!!  If I ony use the 8 inch dimension I come up with 38.20 inchs only .05 inch off again.   The thing is- where do these two dimensions come from? My panels fit pretty well. The rear seems a little high if anything.

  Can anyone tell me where the auto body shops got the dimensions from to sraighten frames ? I know my front rails are off because the right side is 3/4 inch higher than the left. I have no idea what the dimensions on this drawing are coming off of.     
                                                                                                                                                 I think I feel hair falling out,   Phil

[HP2]

    Ok I know that O line is 30.20 inches off the floor and if I add the two numbers from the drawing I come up with a total of 39.95 inches.

There it is! You don't add those two dimensions. They are seperate measurements to different spots. The zero line is 30.2, so if you add 8 to reach the center of the spring eye, your at 38.2, although, looking at that picture of the tape, it appears to be 38.25 or spot on. Notice the 8 and the 2.76 arrows aren't in verticle alignment, so they are not measuring the same thing. I'm not sure what the 2.75 measurement refers to, honestly.

[72cudamaan]

My measurements match when I use the "8". It does seem strange though that
it is the only non-decimal dimension. I agree with HP2, I can't see anything close to a 2.75
measurement. Unless the engineer meant to take the 8" measurement 2.75" in from of
the center of the spring perch.

[brads70]

.5 is pretty good. I've measured quite a few camaro from clips and have found the distance between the steering box and idler arm to vary up to 1" So 1/2 doesn't surprise me. I'd say your good.

[philze]

OK,  I'm happy with the rear frame rail placement.  Now the front, any idea were the dimensions are taken off of?
 
 I'll do some math.  Line O is still at 30.2 inches off my floor, somewhere by the rear of the k member it is 1.74 lower than line O for a height of 28.45 inches.
  Somewhere by the front of the k member the height is .70 below O line for a height of 29.5 inches.
   The only place I get these numbers to almost work is at the spots the k member reinforcing plate is welded on the bottom of the k member. That seems like a very strange place for a critical measurement to be taken!!

   Any ideas? again what do the frame shops use for a reference. What do you guys use when you replace frame rails?

[philze]

Come on you guys!!!

I've seen this same frame spec sheet posted several times when people ask for dimensions, but nobody knows where the numbers come from?
 How did all of you work on your cars and check if the were right???
                                                                                                               Phil

[brads70]

I wimped out and bought a CA car.... no rust issues. 


I wonder if it's refereing to the lower control arm pin and the center of the strut rod hole?

[HP2]

I wonder if it's refering to the lower control arm pin and the center of the strut rod hole?

I'd say the strut rod hole may be the .70 dimension, as it is in that area. I don't think the 1.74  in the control arm pin. That is much lower. It may be the transition point on the K frame from the sandwichied, tubular portion to the tabs on the bolt on stucture.  That does seem like an odd position to place a critical measurement though.

[philze]

   Oh happy day!!!
 I finally got some numbers I can use. These actually make sense compared to the service manual. Now I can start making some forward progress other than cleaning parts. The best $6 I spent on ebay. Hope some of you can use this info, time to get to work!!    I think me hair is growing back. cheers

['Cuda Hunter]

You spent 6 bucks and gave it to us.  Thank you very much!!

That makes sense. 

[HP2]

You spent 6 bucks and gave it to us.  Thank you very much!!

That makes sense.

Agreed, thank you!

[mrbill426]

This should be the same for a '72, right???   

   Oh happy day!!!
 I finally got some numbers I can use. These actually make sense compared to the service manual. Now I can start making some forward progress other than cleaning parts. The best $6 I spent on ebay. Hope some of you can use this info, time to get to work!!    I think me hair is growing back. cheers