It would be best to pull them off (off season?) and soak them. (I guess Fords come off.) Injector cleaners and top cylinder lubes attack fuel pumps. So if you are going to put it in the tank, do it on a day you can burn the tank all the way down and the refill with fuel and circulate it through the pump.
I'm not sure what brand I would use but I'd probably take a big bottle of the Lucas and overdose it. I've poured an entire quart into my Tahoe one time to try clear the spider and couldn't do it (as expected). It is okay for the engine to overdose but not good for the pump so burn it all down in one day and then re fuel.
My boat is carberated, but I have used seafoam on my snowmobile's injectors. First, I removed the injectors and soaked them (over night) in seafoam. Then, I used a 9 volt battery to open the injector, and back flushed each one with an aerosol can of seafoam. I had excellent results. I also used the above method on automotive injectors, with positive results.
I'm sure there are other products that work well too.
I like using Seafoam in Sleds too. When you go through a carb that has started to grow the white fuzzy stuff in the fuel bowls its hard to remove every last bit of it without media blasting. I clean them the best I can by hand and run a tank of Seafoam through the sled. When I've removed bolws after that for jet changes they look brand new.