you have to remember, back in the day, cars were slow, so if you had a car that ran particularly well, it felt like a rocket. i had a little buick with a 231 odd fire in it, we used to smoke "muscle cars" with it all the time.
the cars back then weren't put together very well, so when you had one that had been done right, it really made a difference. it was not uncommon to hear a new hemi, or b.b. chevy had grenaded.
your 307 probably runs better today than you think, but compared to all the twin cam, and other engines of today, it might feel down on power.
just an example, i have a 1961 car life on my desk. a SUPER CHARGED tempest "a whirlwind of performance" 0-60 7 seconds, 1/4 mile 15.5. corvair 0-60 15.5 seconds 1/4 mile 20.3 @ 68 m.p.h.
for the time, and a sequense of good luck matching parts, and your elky was probably pretty quick for the day.
i doubt my 231 odd fire could out run a decent accord today, but back in the day, we gave "hot rods" fits, from stop light to stop light. i loved that car, today, i know it's a glorified vega, and the reason you don't see them any more, is they were p.o.s.'s, but when your young, and speed is new, they felt like they were flying. in high school, i was lucky enough to drive a friends sorted out 454 nova, then i knew there was a whole nother world of fast...