The biggest difference is the enclosed enrichment valve which helps tremendously in a cold start scenario.
New materials allow for ethanol mixed gasoline without the worry of wearing out the carb prematurely.
They're configured with a flow through fuel bowl, it's also much cleaner looking installed.
50 years of improved manufacturing materials and processes go in to making these babies, compared to the originals.
Tons of needles and seats available off the shelf from SU to accommodate any project.
We should have dyno numbers soon that compare the original hs6 carbs to ours.
Here's an installation we did for a customer, it's a super-clean 260Z. In the picture, the choke cables and air cleaner are not installed.