I have a 360 that I race just for fun. It has a rough idle cam. I have been trying different carburetors just to see if there is any improvement. But I have developed a problem that is driving me crazy. The engine will start right up and will run great as long as you keep it about about 1500 rpm and up. I had a holley double pumper on it and I thought that was the problem. I changed to another double pumper same problem. Now I put a nearly new edelbrock thunder on just to eliminate the holley could be problems. I have the same trouble with the edelbrock. I figure its not the carb. So today I started on the electrical system. It has a stock electronic mopar dist. with light springs and chrome box. I took the distributor out and checked everything it seems good, bushings tight, springs in place, changed the cap and rotor. I have the timing set at 32 degrees advance at 2000. It wont idle at all so I don't know what idle is. It also seems like a vacuum leak possibility but I have checked the intake bolts and replaced the carb/ manifold gaskets, don't see any place for a leak. Watching the tach there is some rpm variance at slower speeds like 1500-2000. Anything under about 1500 and it dies just like I shut the switch off. Has anyone had anything similar I am at the end of my check list. Thanks