I have a big block 454 in my K5, and the short fuel pump style out of a K20 with a 350. It ran fine and kept pressure in Ohio, but I just moved to Colorado. It worked fine here for a couple days, the started losing pressure. It finally gave out completely. I replaced it, and this pump seems to not be able to keep pressure either. The fuel pressure sender in between the pump and the carb. I'm thinking that if it was a fuel filter problem (filter replaced in October with carb rebuild) it would increase pressure or read normal. Could I maybe be sucking air into the line through a rust hole? Or is this new pump just crap? Can someone tell me a big block that used the short style pump (the long style won't clear the crossmember)?