Seriously back in the day[1980s] saws were no different in basic design then they are today, besides the new strato charge saws. Now the 181 Husky came out in 1981 and besides not having air injection I would still call it a modern saw. The biggest increases in power in the day was sticking a circle crank into those guys along with some good porting, big carb and this still stands today in the stock appearing competition class.. Now I wouldn't recommend a circle crank in a woods saw .LOL.
In 1988 with a little hairpulling i got my 1986 Stihl 064 fitted with a circle crank and still retained the factory cylinder without a cutoff head. With the 084 carb, deep finger porting ,indexed plug for starters,she still in 2008 puts a big grin on my face.