So I currently have a 455 with a Holley 650 spreadbore stuck on top. My main question is what came factory on these Pontiac motors. After a ton of research I have come up with that it is a q-jet 4 barrel. My carb has been tampered with by the previous owner. I was told holleys are a pain to keep tuned witch is why I'm looking for a replacement. Can I source a rebuildabke core from a junk yard if so what car/engine combo. I'm still new to carbs so any info is greatly appreciated. And yes I can handle flaming as long as there is good info along with it.