My original plan was a pair of single-barrel injector pods on a 2 carb manifold. After a lot of thought, I decided that there was going to be a lot more work for a minimal gain with that plan, so I'm just going to be using a 2-barrel TBI on a manifold for a 4-barrel carb. The injectors I am using are for a 4.3L V6 (the 250 is 4.1L), if they prove to be too small I'll go up to the 305 injectors. It will be a while before I have any results, the whole truck is progressing rather slowly. I'm also converting my HEI distributor to computer control to complete the system, but that is another story entirely.