Before you go too much farther, I would throw a fuel pressure gauge on it and see if the fuel pressure is dropping off when you lose power. That sounds more like a pump failure than a dirty injector to me.
Yes - and the Fuel Pressure regulators in those can go as well, which can cause similar issues. Has a flexible accelerator-pump like part that the spring bears on, which can crack; and a spring that can get weak or break. The FPR is inside the TBI unit but is easily repaired without completely removing the TBI unit as a whole, just have to remove the lines and IIRC 5 screws and the assembly lifts off. Make sure you get gaskets before you start.
Also - with an EFI swap of any sort: Check the sizing of your feed line (I'd recommend 3/8" for those) and make sure the return line routing is functional. There are some creative workarounds I've seen, some of which can work under most circumstances but that can cause issues over time or under load.
