I Called B.S. on This
I had a 79 T/A with a very anemic 403 Olds engine. POS motor. Rated at 180 - maybe on a really good air day in Death Valley. Put headers and a Holley on it - just made it worse I think. Threw the cat over the back fence, etc. - all the standard stuff we did back in the Disco era.
BUT...One evening I received an official "clocking" by the Fort Worth Police Department at 145+ MPH. So a 250+ HP motor might get 150~160, given sufficient room and luck. Now, it took nearly 2 miles to get there but I blew the doors off those two Camaros in the process...
1967 Falcon 4 door 351C - 70 Mustang 351C
Owner built, owner abused.