I need schooling - old vs. new engines

Another example: My son's 73 Scamp. FACTORY 6.1 long block with a 230s @ .050 cam and Cascar intake. 750 dp. 3400ish race weight with me in it. 235/60 ET street with 3.91 gear. Best so far is 11.81 @114. Not close to the horsepower in question. Just another example of junk.