I have been thinking about a swap like this for a while. If you watch eBay for used carbs off sport-bikes like Ninjas you can find sets of four pretty cheap. I'm doing a 4 cyl. so that's all i need but I got them for $30. You should be able to get a couple sets for under $100. I haven't had time to do anything on them yet. With 6 carbs you will have to make some small things like linkage to run them all and a bracket to hold them but I would think it is do-able. There are kits out there for some cars like Triumph TR6
but they are pricey. I don't see why you couldn't do it yourself and save a ton of money.