It is a rare mechanic indeed who has experience enough with manual
transmission 164s to give advice without looking at things.

My 164 had a very heavy clutch. I had the clutch replaced when
it wore out; the clutch remained heavy. The clutch cable broke so
I replaced the cable with some wire rope (steel cable) that I fished
through the existing conduit. The clutch was heavy. The mcguyver
repair eventually started to fray and was irritating so I replaced
it with a proper OEM cable clutch. It was heavy (though smoother
than with the other 2 cables).

The clutches on 164s I've seen in salvage yards also were heavy,
though I have no idea if they were properly adjusted.

I think the moral of the story is.... 164 clutches have stiff
springs. The action should be smooth and there shouldn't be any
squeeking when you depress the clutch (my old cable quacked like
a duck towards the end) but otherwise, I think it's normal.
chris