Any IR intake system runs best with a cam that has a wide LSA and minimal overlap. Because there isn't a common plenum, the runners are subject to some pulsations as the valves open and close. If there is too much overlap, you'll develop the dreaded Weber fuel cloud at lower rpm's (like, <3,500)
As said above, the balance is critical. If it's not exactly right, it will never run well no matter how you tune it.
The linkage is the first step. There should be very little slop anywhere. And it should be infinitely adjustable. I messed with mine for a long time, until I finally trashed what I had gotten with the system and started over.
Second, you'll need a balancing tool. This synchronometer worked well for me:
https://classiccarbs.co.uk/product/w...rsynchronizer/
And, finally, you'll want some kind of vacuum source. Preferably a small plenum. Some Weber type manifolds have them, and some don't. If yours doesn't, consider something like this:
