I recall those JBLs specifically from years ago working at a Tech HiFi part time during college.
Speaker and amp technology and options have come a long way since then. SO its hard to compare stuff from back then to today.
I would feel confident in saying that there are many ways to do much better these days than was possible back then.
Having heard and demoed both on many occasions, I always preferred the OHM line to JBL back then. OHM is still in business and when available still sells their old models/cabinets refurbished and with updated components, drivers etc, for not much more than they cost back then.
The old OHM's most comparable to those JBLs would be the C2s or Hs, I would say. Hs were perhaps my favorites in the whole shop back then, though tonality of C2 was more like JBL as I recall. Contact John Strohbeen at OHM and I would bet he could whip you up a new and refurbed pair of Hs or C2s for a price that will remind you more of the 1970's than what something similar might cost otherwise today.
Or, for fun, if DIY has appeal, maybe find a pair of L100s on ebay and rebuild them yourself with more modern components and see what you might accomplish. That's what I did a couple years back with my old pair of OHM Ls from back then, and they probably sound better than ever, especially in that the gear I feed them with these days blows away almost anything that was available back then.