Hi markmakeitso, welcome to mightyram. A non functioning secondary vacuum actuator on the carb would not normally cause misfire. You can swap the dud secondary vac without pulling the carb off but it takes a bit of leverage. The distributor might have a broken counterweight advance spring in it, causing the distributor to over advance. I would personally try dialling the ignition back and tuning it by ear or at least pointing a timing light at it to check the base settings. The Ford carb body injection will make an interesting alternative to the traditional weber 32/36 carb install. They look a lot like the weber too so I bet it will be a relatively easy thing to set up (might be able to use a weber adapter to mount it).