1986 F150 5.8L 4 Barrell carb. brand new rebuilt engine just installed. new rebuilt carb and fuel pump. aftermarket stock dizzy and ignition box. new exhaust with 2 cats and flowmaster muffler. a bunch of vacumn lines, some of which i have not figured out where they go. so here we go. go to start engine for the first time, it starts right up, runs good, idles fine and let run about 5 minutes and then i shut it off to hook up timing light. get the new engine smoke but i smell almost something like burning plastic burning. look under truck and the cats are red hot. let engine cool for 10 min. and go to start engine again. this is where the problem begins. i have to floor the accelerator and the engine starts to stumble as it starts almost like its flooded. continue to crank engine over and its starting but never runs correctly or opens up. leave it alone for a day and the exact set of circumstances do it all over again the next day. can anyone figure out whats wrong with this picture? any ideas would be appreciated. i did order a new y pipe to delete those cats to see if maybe thats the culprit.