Hey guys, been reading around on here for a long time but now I've got a problem and thought this was the place to ask. I just swapped in a vortec 383 into my 97 k1500, the issue I'm having is that it doesn't seem to be getting fuel to cylinders 2,3, and 5. I checked it by wiping a wet rag on the headers after it's run a bit. I pulled a plug and it's got spark. Does this sound like the poppets being uncooperative after the swap or could this be timing related? It doesn't start very well and really stumbles below about 1500rpm. The higher in the RPM range you get the better it sounds. I've also done the 0411 swap if that makes any difference, it's also throwing a P1336 code, no others.