carb issues

Disconnect the secondary link and tune the carb on the primary side first.
Do this with the 70s up front and see how it runs. If it stumbles jet up by 2s.
Once the primary is good hook up the link and jet the secondary.
Also make sure pump shot is adjusted correctly. A very light tap of the lever and fuel should shoot.
1/2 to 3/4 is when the secondaries are opening.
I assume your fuel fuel delivery is working correctly, 6.5 psi and good flow.