I recently rebuilt my 350 and it just doesn't want to run. I had the block machined, rotating assembly balanced, and bearing clearances checked by the machine shop. It has Speed Pro flat tops, a 300 duration cam (232 @ .050)/.488 cam with 1.6 rockers, Jegs 180cc aluminum heads, a Pro Comp single plane, and a 750 Quick Fuel Slayer with a 140 gph electric pump set at 6 psi. I tried installing the distributor 10 degrees advanced on the tab which resulted in a 4000 rpm idle and then reinstalled it at 0 which tamed it down a bit. Now... it will run but only if I keep my foot in it and once it hits 2000 rpms it'll die. I tried more advance, less advance, and I hit a sweet spot where it wants to start right off the bat but it won't unless I give it gas. The engine sounds healthy when its running but its very difficult to get a timing light on it when it won't hold an idle. It'll run ok with the choke closed but once its warmed up I can't get it to run on its own for the life of me. What should I check? I know the basics like timing, carb tuning, and fuel pressure, but now I'm getting irritated. I really don't know if its a timing issue or a fuel issue. I pulled the plugs and they're a little black but it also smelled fairly rich from the few minutes it ran. I'm fairly new to holley style carb tuning but it seems like all carbs are pretty much the same.