I got an 83 c10 with a 305. I replaced the trans and once I did that I started finding problems. No spark I replaced hei distributor new plugs and wires. Started up fine but was having major carb issues I rebuilt the rochester q jet in the process of that I saw alot of damage from sitting pits in the bowl and other areas. Replaced carb with edelbrock performer. Fuel pump went out on first start so I replaced that with stock mechanical. Full vac system rebuild due to running really high rpms even with adjusting carb and distributor. I did full vacuum delete except vacuum advance and pcv set up that made it run a little better but now timing is advanced and it must be fully choked to start and I have to hold the pedal at half throttle till it warms up so it doesn't die. I checked vacuum at manifold and it sits at 10 hg I hit or hold throttle and it drops and holds at 0 I release throttle it shoots up to 15hg and drops back to 10hg. I am freaking stumped I've sprayed carb cleaner everywhere to check for vacuum leak and nothing I don't know what to do or check.