I did the conversion and Stan's 4.7 liter is a 286 - My little '66 Mustang had a 289!
My F/250 6-liter could be considered overkill, but then again, it was never working very hard. The trailering package gave it not only the trailer brake controller in the dash, but a beefier transmission and torque converter, larger transmission fluid cooler, a tranny temp gauge, larger engine cooling, bigger condenser for the A/C (part of the "Southern Truck" Package) and a few other things I can't remember (Oh, and the dual DVD hook-up for the back seats, too). All THAT was the overkill part. The PO was a lady who hauled a 4-horse trailer so figure 1,600 pounds per horse and another ton for the trailer and you get the idea of why all the beefiness.
Let's see what I remember... My 6-liter was pushing 560 ft. lbs. of torque. I never chipped it. At 70mph on a flat with no headwind it would run around 2,100 rpm and the boost would be around 10-12. Going up that 11-mile-long uphill on I-81 from NC into Virginia in Cruise it would remain at 70mph and the revs would increase to 2,300-2,400 but at the steepest part, near the top, the boost would be pushing 40 (!!) and there was this sinister snort to the exhaust. Kinda like Pearl's exhaust note!
Ahhhh.... The good ol' days!