1978 with 305 and quadrajet. The engine was running perfect but since I had nothing better to do I decided to rebuild the engine ( plus engine was really tired). Replaced rings, crank, timing gears and chain, etc. When I finished it started right up but I can't get it to idle. Runs at 1500rpm and when the high idle kicks down it's still at 1500. All the linkage is loose. I've checked for vacuum leak and found none. The idle screw was turned out so it doesn't even touch. Choke works perfect. Moved the timing both advanced and retarded with very little difference. Anyone have any ideas ?