Pick up any Hot VW's mag and just about every trader that does engine parts sells a kit.
They're dual single throat carbs, like Kadrons I guess. There's similar kits from Weber & Solex. I think Hot VW's did a comparison a while ago but I cant remember the result, it was pretty close, maybe slightly in favor of the Solex's but don't quote me on that.
Kits go for around $320-350 US new, there should be some on ebay
1954 Oval long term project going nowhere
1958 Beetle drag car project
1959 Beetle project I need to sell one day
1969 Squareback