I just installed this system on my 410.
What is your vacuum at idle? Any efi system likes a wider lobe. Mine is on a 112 and 236/243. Your 110 and long duration for a 340 is going to be difficult no matter what efi system you use.
It should idle with 12 deg. I wouldn’t be concerned with 750 rpm. A little higher is ok.
In order to lower the IAC, you need to OPEN the throttle not close.
How did you fit the distributor? I shortened mine 3/4”.
Feel free to call me as I have lots of efi retrofit experience. 516.384.6438
View attachment 1715575663
View attachment 1715575664
