Coordinates of trailing arm suspension parts

[kingcrunch]

Hello there,

my second post here goes right into the details.
I am building a 1985 Dodge D150 (hear me out) into a race truck. Autocross, track days and road racing is the focus.

Now what has that to do with Chevy?
I want to put the trailing arm suspension of the 60-72 trucks (i know there is differences and they split 66/67) under my Dodge to get a good suspension system under its tail.
Leaf springs are not what i would want to use with a 650hp (ultimately, starting with 485) truck.

I have read of a lot of advantages (defined instant center, tuneable roll center, coil springs, rear steer, no axle hop, no spring wrap, etc.) over a leaf system.
But what i was not able to read about are dimensions.

I have a set of arms and i need to build a crossmember for them because the Dodges frame is wider than the Chevies, i made an overlay of a C10 frame and a D150 frame that makes that a bit more visual:



I have a few questions about measurements i would like to ask and it would be extremely helpful if one could help me out.

Thanks.


Let's start:

In this picture of a stock crossmember there's three different colored arrows to show which measurements i would need.
I figured a picture is easier than a lengthy passage.



And i would need the center to center measurement from that arrow so i can space the axle pads correctly:




I work with pictures a lot, there is a lot of info in them.
I don't always know whether the info is correct.

From this picture i obtained angles for the trailing arms using a 2d CAD program (LibreCad).



The angles obtained are:
- 16.5 degree from centerline
- 33 degree between the arms

Could anybody please confirm or correct these?


Thanks a lot!
Alex


P.S.:
Some of these pics might be courtesy of users of this site, i don't remember because i just right click and save everything i find useful for this build.
If you own this pic and don't want to see it here, drop me a line.