Get some 1/4" solid round stock and bend a mockup piece to where you like it. Leave some clearance to interior panels ect. Then when you like it use it as a template for your final piece made from 1-5/8" or 1-3/4".
Before u decide u are gonna do this, keep in mind there is much more to it than you think! Replace all of the body bushings before you measure for anything. That will change the height of the main hoop. The main hoop welds to the frame, so do the front door bars. The rear sweeps weld to the trunk floor above the axle typically, but the better shops weld them to the axle hump in the frame, that's the preferred way.
If you are EVER THINKING about doing urethane bushings, you need to do that first.
When we did bars, we lifted the body off of the frame at least 6"+ to weld the tops of the rear sweeps to the main hoop, and clean the frame thoroughly so you can get nice solid welds to the frame. If you have never done bars, or are not a professional quality welder with professional equipment, you most likely will lower the value of your ride trying to do this yourself.
Nothing screams cheapskate and low quality like opening the drivers door and seeing a poorly fitting bar that has low quality welds. That makes the tech inspector and/ or possible buyers start looking for other places where you skimped on safety or quality.
A top quality bar follows the interior contour of the car closely, it's not just a straight bar with two bends.
BTW, has the person that might give you dimensions replaced his body bushings?
Did he or are you going to jack up and square the frame before doing any work or measurements? If the frame is tweaked now, its gonna stay tweaked once the bar is in. Then once you add the HP, is it gonna go straight? Have you seen the quality of his work? Do you trust him with your life? Or even that his bar is actually legal for competition?
Just some things to think about before you may end up rolling or flipping because your trans exploded.....
I wont give anyone dimensions because I wouldn't want to be responsible for them possibly sticking something together with a Harbor Freight 110v. welder....
Not sayin' you actually would.....
For anyone that plans to track the car..........Get a current NHRA rulebook.
There are lots of "little details" that can get you crossways with the tech guys.
Built in my shop with S&W 10 pt kit.
Kit was almost "OK" from a fit standpoint. Moly 1 5/8.
The main hoop was supposedly bent using a shop GN as a pattern.
Didn't come CLOSE to fitting, requiring a pissing match with Mr Barton.
"RTFB" when doing such a project!
So, it can be done at a home shop...Takes a LOT of time!
BTW, this car one won "best engineered" at a NHRA division meet.