As you have the manifold I'm assuming they've been removed from a 6n polo? if so then you'll just have to have some kind of ignition management, not to sure if you can use standard 6n ignition though. I'd have said that it should start and run but you'll need to get them balanced so all 4 carbs are drawing in the same amount of air, making the mixtures pretty much the same on all carbs. I had twin weber 45's on a 2.0 16v in my mk2 golf and the only problem I had was massive heat soak from the radiator when stuck in traffic, went 20vt instead. There's a garage in Broughton called A B garage, they set my carbs up and there pretty reasonable too.