I have the exact same car. I bolted on a twin HS6 S.U. set-up in March and have no regrets whatsoever. I bought the set from Jeff Palya at Paltech. For $550, I got two refurbished and polished carbs along with a shiny intake manifold. The car runs like it did when it came off the assembly line in Gothenburg--lots of torque, smooth idle, and easy morning starts.

I've owned Volvos with Weber, Stromberg and S.U. set-ups. I'm convinced that each has pros and cons, but if you want the best blend of performance, ease of use, and reliability, the S.U. carb is the way to go.

Best of luck.