Personally, I'd go with the smaller 40s. I have triple 40s on my L24 and they are awesome. I have an upgraded electric fuel pump, adjustable fuel pressure valve too. You'll need to customize the Webber linkage or you'll find the triples will get hung up the longer you drive the car, the higher your idle RPM will climb. I'd also recommend ceramic coating your headers and the biggest possible heat shield under the triples. Without the heat shield, fuel will boil right out of the carb closest to the fire wall. Ask me how I know.