As your car is a 1986 model, chances are that the carb is a Solex Cisac. Not the best carb for performance. But, a Weber 36/36 DCD will fit almost directly on the existing intake (B230K). "Almost", as you need to file up the mounting holes on the carb about one mm. This is a normal upgrade for the carb'ed Volvo B20-B230 engines in my neck of the woods, in fact I got one myself for my 1987 240. You can also find used Weber 2x45 carbs (you'll need a matched pair) for reasonable prices, in which case you also need a new intake - and an amount of spare time for all the tweaking required.
Then you can of course drop in a hotter cam, but this will typically move the powerband upwards. If your driving is mostly around town, consider the fact that you often need to pull 1.5 tons from zero mph and up to speed, and will need all the pulling power you can get. If most of your driving is on the motorways, and what you want is power for overtaking, a K-cam (for instance) won't be bad choice.

Erling.
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