What hedmans you using?
I have a 72 car but with a 73+ k member. For disc breaks. I have power steering and brakes. And I got my hookers to fit. They are the "too low, drag, don't fit right, have to disconnect the steering" pain the *** headers that everyone here loves to hate. But they were 200 bucks.
To get mine in the passenger side was easy. The drivers side was a pain in my ***.
You mention you have the car jacked up. But have you jacked the engine up? Here's what you do. Disconnect the motor mounts. Should be spool type. With the car low enough that you can put a floor jack under the oil pan and still jack it up. You MUST put a piece of wood between the jack and oil pan. And this piece of wood MUST extend past the sides of the pan. This way you are putting stress on the wall/sides of the pan. Not just on one small hole in the center. Which will surely fail. Then jack the engine up. You can probably get between 4-6 inches without having to disconnect anything else (watch the distributor cap though. It gets awful close to the firewall). I think I got close to 6 out of mine. This will give you MORE than enough room to fit everything through. Mine went in through the top fine like this.
Now. That's assuming you're using the cheapy below the steering linkage setup headers like I did. If they are another type. All bets are off.