I feel it is time to upgrade my 1977 system.......

I found that inexpensive new amps are much better than "vintage" amps... 

how about a new integrated from Anthem, or Arcam, or Marantz?  

These days, you don't have to spend a fortune to get excellent sound, fortunately.  You can spend 18k if you want to... but you could do great for half that or less.

If you're intent on keeping the Altecs, OK... but speakers too have come a long way for the money.  If you like lively and yet with that "audiophile classy sound" and old-school looks: Klipsch Forte IV.  aprox $5000

Neutral and refined and pull a "disappearing act," perhaps something like the Q Acoustics Concept 50, aprox $3000.  

@pdreher I agree for the most part and myself I own and love Epi 100 speakers and their little brothers Epi 50, with some updated parts from Human Speakers.

So, as I don’t know the Altecs in question, I don’t necessarily assume that new speakers are "better" than those... though I’ll note that even you have refurbished Altecs.

However, that said, speakers, like amps, have come a long way in "bang for the buck" since the 70’s, especially when you factor inflation, and there are some relatively inexpensive, $2000-5000 range, choices that perform at an astounding level that only the very, very best from "back in the day" could aspire to. Think about the updates over time to the JBL 100, the KLH 5, and the Klipsch Heritage... There are also far more choices in even less expensive "budget" speakers these days that only a select few from the 70s could come close and that only if updated.