Here is a video of me  and Nick at G&R race prep in Monrovia synchronizing a set of dual carburetors 40 mm webbers 
These are real Spanish, Webbers, and is usually what I prefer. I do not like China carburetors. Here’s a simple procedure of how to get your carburetors to run crispy and to react the way they should carburetors feed, fuel and air into an engine in a mechanical way via vacuum signal , all you have to learn how to do is listen to the engine when it’s speaking to you.