250's make 155 horsepower stock, usally but that's the number they slapped on 250 6cyl Camero's in 1968, and that's a generalized number I go by cause I remember it as my friend has a 100% restored '68 RS Camero with the stock 250 6cyl and a powerglide and he has all the original documentation and it all says 155 HP, also, www.carnut.com says the same thing. 250's can be built up to almost match hp per cubic inch, with the after market parts made for them, the availability to mount a 4-71 Blower on them, or lotsa carbs, they can be built to motor, 292's are better but, I was watching dragracing on speed and there was a guy with a '68 Camero that had it's original 250 but it was a pro street, the engine had been custom built with even custom engine internals and a 4.71 Blower and NOS, it was said to run 600 without NOS and like 725 with NOS, I can't remember his times though.