For many years, at least 40, I have loaded a 140 grain JHP over 9 grains of SR 4756. From my 6 inch Model 28, my chronograph shows a bit over 1200 FPS. Good accuracy, but it does recoil a bit.
Sounds like you found that load in the Speer #8 Manual. It had(has) a reputation of having starting loads,especially with SR4756, actually being close to max loads.
found it there yes, back many years ago. 1970 edition. I have played with the charge, going up and down. The 9 grains gives a good compromise. Fast, accurate and fun. It is a good load in my Model 60 three inch, instead of using a .357 mag load. With some 40 years of experience using the load, I'd say it was spot on for a 'max load'. No complaints here.
