What is a good 1960 to 1970s muscle car?
"...decent engine, handling, chassis, brakes, etc" None of them.
A new Honda Civic Si coupe will smoke any stoke traditional muscle car in any sort of race, expect maybe a straight line of a ½ mile or less. The new Si has 197 hp net by current measurement methods - that translates into about 300 hp by mid-1960's measurement methods.
On most of the traditional muscle cars, disk brakes were an option, or not even available. A new car will stop from 80mph in a bit over 200 ft. Traditional muscle cars required 300 ft or more.
Handling - dream on, a new sporty Corolla or Civic will pull well over 0.8g on a skid-pad. Even the best traditional muscle cars were at 0.7g, and typically around 0.6g.
Fuel economy - in a traditional muscle car, getting over 10 mpg was considered very good.
Just based on your question, there is no way you should drive a traditional muscle car, you would not be able to handle the lack of modern brakes, handling, efficiency, etc.