It probably won't make a massive difference at the injector timing tbh. Think of all the batch fired injected cars. The charge will just sit in the port till its ready. Which is fuck all time. (300ms at idle if my calcs are correct).
Definitely something wack with your timing. Maybe even your cam timing is off?
Also, there is a little stub that sits down the dizzy hole that drives the dizzy/PI pump in the PI cars. Check that this is in and timed correctly if your crank pulley is correct.
Also also, do a compression test to check if the motor is actually legit. And Yeah, as handsome Blizzo said, any air in PI lines will stop it from working peoperly. The injectors need over 100PSI to open and squirt properly. So if there is air trapped, it will be absorbing precious PSI, so will be running lean. Weeping injectors also won't help.