I'm not going to try to address the issues of how much low-end torque which cam may or may not have.
In my experience, that can vary significantly with the headers, intake, ignition curve, static compression... ...and that's not taking into account other factors, such as vehicle weight, gears, etc.
A first-generation a body, with a stick and 4.56 gears would certainly not suffer greatly with extra duration, compared to a fully optioned b body with an automatic... that's another story, isn't it?
Anyway, this discussion is really just about what will fit in the engine and not get damaged. For years, my modus operandi was to start at the bottom of the page of the cam catalog, and work my way up until I found something I could assemble in the engine without crashing parts together.
The Harley-Davidson guys can generally see what the TDC lift figure is on a lot of grinds in advertised literature. I don't think that's commonly published by automotive cam grinders, however, if you were to contact the manufacturer, I'm sure they could furnish that information
Of course, this will also be affected by who are the cam is installed. Change the center line, and you will either add intake clearance and remove exhaust clearance, or vice versa. Depending which way you move the cam.
Since the OP was talking about porting some heads, it would be simple enough to assemble with checking springs, put the head over a cylinder with the piston @ TDC, and see how much lift his engine will take @ top dead center. And, it would not be a bad idea to repeat that measurement at 10 degrees before and after.
I strongly favor making a measurement like this, as opposed to relying on anecdotal evidence as to what may or may not "fit".
Then with data suppliedfrom the manufacturer of the camshaft, it should be pretty easy to know if something is going to be able to assemble safely or not.
Just remember, what may work @ a given RPM range may not be kosher at a higher engine speed. I have made some offerings to the gods of speed to learn this lesson...