I have in my possession a 1969 Olds service manual for everything from F85s to Toronados (it's about an inch and a half thick, paperback, and cost five whole dollars at the time), but, while the pictures and line drawings are great, and the wiring schematics are amazing, I didn't see a lot of actual measurements as I flipped through it.
I did have one idea, though: Car and Driver and Road & Track both tended to have excellent data pages on their test cars back in the day. (Maybe they still do, but the OP wants 70s stuff.) R&T even used to do scale profile drawings on a grid. Depending on what you want, you could probably find it in there somewhere. Unfortunately, AFAIK (and if I'm wrong, please let me know ASAP!), neither publication has followed The New Yorker's lead and put every single issue on line, so you'd still have some brute-force searching unless you knew what specific issue you wanted. But the truth is out there.
PS Also, some model-specific forums have scanned copies of old brochures available for reference on their sites.