70" 340 vs 72" 340 specs please

The factory 275 is a gross under-rating as pointed out. The cars made more the 68-71. I don't know how accurate the ratings were on the 72 and 73 but the early ones were really 320hp@5600 rpm. Note the stock 340 may very well have made 275hp@5000 rpm but it wasn't done pulling at that point! LOL!
Also note thats more then the real numbers put out b the boss 302 mustang or the early 302 z/28 motor which both made 310 hp@6200 rpm.