[Trent7276]

My engine is a 1971 400 so I set the timing at 12 deg, same as it was before the swap when I had the Rochester. Today I fired it up some more but only one backfire out the carb all day...the rest of the time I'm just trying to keep it from dying at 1000 RPM idle. At 1000 this engine and car feel like they are shaking violently! I must have too hot a cam in it? I must have a problem since it gets a really loud "sucking through a small hose high pitch" sound when I try to get it down to a 1000 RPM idle. Also, initial testing shows vaccum pressure at 15 when 1500 RPM, then I let off the gas and let it drop to 1000 RPM, vaccum goes to 6 or 7, sometimes stumbles to 5,4,3 and dies. I'm not even running my Power brakes but the hole in the Carb backside is plugged as they suggest if no Power Brakes. I've tried the tuning procedure to no avail from Edelbrock. Some help on how to tune this thing?? Why is vaccum so low now and not before. Is it the new RPM Manifold? With the stock manifold and Rochester, I would get a good 15-16 Hg at 1000 RPM idle. Initial thoughts are my cam is too hot, my #47 heads are sufforcating my engine, and I might have a vaccum leak...anyone else?