Another D/Dart 275/273 question???

hi, I been reading about the 273 motors here. back in 1972, we had a 65 dart 235/273, it was a legal stocker. had the trw pistons, lunati stocker cam, 5.13 gears, 7" slicks, 4 speed trans, stock heads, with 3 ange valve grind, best it ran was 13.31 @ 102.31. I can tell you it didn't make 400hp!!! more like 250 hp, weight was 3150 . today's stocker 235/273 will run 11.70's , @ about 109 mph. they make around 320 hp. your computer program is very optomistic!