I've collected older Japanese (1969-1971) FG's for many years. They're called 'Red Labels'. They sound very loud/warm/bright at the same time.
Recently I sold my 1970 FG-180 to my step-father and these days he really enjoys this guitar. About a year ago it's been refretted and it played
like a dream after that. I was really obsessed by the FG-180 (owned two of them), for sound, playability, looks, mojo, history, just everything.
I can remember an old, well played-in 70's Japanese FG-375S (with solid top) I had about 4 years ago that sounded out of this world; extremely sweet and bell like when fingerpicking and it played better than any acoustic I've ever touched. What a jewel that was! Sold it, like every great
old FG. I really regret that!
My favorite Yamaha these days is an FG-340 from 1980 I still have, very loud and punchy. It's great for acoustic rock, especially when strung with Elixir 11's.