i made one using copper fittings, the outside fittings fit perfectly OVER the mounting spot on the carb. I noticed an extreme increase in performance but i think it was because i had a leak and it was getting more air.
dont do it,i did it using copper fittings and now it takes me 4-5 times to start my engine and my carb bowl leaks a little.and i jb-welded everything and had to buy another carb and intake for $38no performance increase with this. but i know the sizes of the copper fittings if you want them.
its better to just make a custom aircleaner than to move the carb.
or you could buy the carb that doesnt use a intake(it has flange built in)but i dont see anyone selling it separate from a engine kit.