The answers are "right in the book." Go over to MyMopar and download a few shop manuals over the years. 67 is a "good year" as that included B /RB with AFB and hemis. 69-70 would add in 340 with a Carter, "before" ThermoQueen came along.
I think the "fussy on pressure" deal came mostly with "modern" chineseoated needles and seats which don't seem to tolerate pressure like they ust'ha.
Below are 67, 69, 70, and 72 pump pressure specs Notice that some of them are over 7 1/2 psi.
In the 70's I never CONSIDERED running a regulator, or even bothering to check pressure unless I perceived a problem. I used to run a big solid state pump I can't remember the name of, and one of the Carter motor drive pumps when it first came out.
