In the process of getting the brake lines and hoses replaced but this is getting ridiculous. I bought the 82-83 Front to rear line (standard fittings) from Inline tube as suggested by them after the first one Camaro Central sent me was incorrect and way too long. I sent them pictures of my stock axle setup. They also suggested the 84-88 hard lines to the calipers with metric fittings. So, the hard lines won't thread into the brake caliper hoses and the front to rear line is too small to fit in the center hose threads.
Part numbers: Rear center hose Dorman part H3180 (metric M10 and M12 fittings) Rockauto for 83 Camaro
Rear caliper hoses Raybestos 38188 (SAE fittings) Rockauto for 83 Camaro

So, I might answer my own question here, but it looks like I need different hoses?? I can provide pics if it would help, thanks.

 

82 & 83 had SAE fittings everywhere in the brake system.

85 up had metric.

You may ask yourself, what about 84? Well, the changeover was sorta midyear. Some 84 cars are all one, some the other; some are part one and part the other, although very few seem to have suffered that jerry-rig; it's rarely predictable though, even by build date, although early tend to be SAE and late metric, for obvious reasons.

Your car should be all SAE, unless somebody has swapped something out in the last 40ish years or so. Not that anyone would EVER do any such thing, butt... who knows. It's too dark out right now (just past sunset) for me to see your car clearly and tell you what it has. Sorry. Besides, I'm hundreds of miles away, so my optics are probably not good enough to resolve your threads, even in full sunlight. Sorry again.

In any case, your fittings ARE what they ARE, regardless of what they're "supposed to" be. Odds are though, it being a MAJOR PITA to change from SAE to metric in one small random place (both ends of a steel line have to be the same for example, therefore both the hose end and the PV fitting have to be the same, and stuff like that), that your car is all SAE. ANY metric parts will NOT fit it in that case. You got bamboozled.

 

83 rear disc brake

83 Raybestos hose on left compared to original

83 hard line from Inline Tube will not go into original rear caliper hose.

83 hard line from Inline Tube will not go into 83 Raybestos hose.

 

That hard line is a metric bubble flare. It's not 83, it's 84-up. The original hose has a SAE 45° inverted flare, correct for 83. No surprise they won't mate up.

The new hose in the 1st pic looks right but it's hard to tell from a photo. The angles of things down in there don't come across with a camera very well.

 

Yeah, the bubble flare will not allow it to grab the threads on the factory hose or the new one. So, I will reach out to Inline Tube. This is the second set of rear lines they have sent me that don't fit.

 

New lines from Inline, with standard fittings. 3rd set is a charm.

83 Camaro: Correct line with Standard fittings, driver side. Goes into brass fitting/caliper.

83 Camaro: Passenger side goes to hose.

 

Nice!..