My allergy kitty also will throw up food that isn't agreeing with him. It's been so long since that happened that I had forgotten about it. But some foods will come up almost at once. Some really "at once." Beef comes right back up. One urinary formula wet food (a chicken food) that we tried because the ingredients looked good - not because he needed a urinary formula - absolutely bounced: He threw it up right back into the bowl he was still eating out of. When I first got him, I gave him kitten chow (dry) because that is what I had and it was the weekend. It stayed down maybe 12 hours, then *all* came back up, undigested. He was all of 4 months old. The bigger problems didn't start until he was closer to 2 years old.
For him, a high-quality food without grains in the slightest amount made all the difference. It has been ages now since he puked. I actually can't remember the last time it happened. Before I had him on the Wellness, puking was a several-times-a-week-in-a-good-week event. In a bad week, it was several times a day. And if things got bad, he would get diarrhea. Then asthmatic coughing. What fun all that was! :?
For a long time I was convinced that he was allergic to chicken, which turned out to be an excellent food for him. All the other chicken flavors I had tried had other ingredients that got to him. I thought it was the chicken. Now I know it wasn't (but I still don't know what it was - beef is a no-no, but there has to be something else, because a lot of the foods that made him sick contained no beef.)
Keep trying various foods. I know how tempting it is to pin the problem on the most obvious thing - for me it was chicken, for you it is dry food - but that may keep you from discovering the real culprit (or discovering a "magical" solution).