My '62 Fairlane has a 170 ci and two speed automatic. It has a Holley 1909(list 2345-1) carb and the load o matic distributor. The engine falls flat on its face and won't rev above 2500 rpm. I've cleaned and rebuilt the carb, replaced the steel vacuum line and vacuum advance canister on the distributor. The initial timing is set at 12 degrees BTDC. I timed it with the vacuum line disconnected and plugged. As soon as the engine is revved up, the timing mark advances properly to maybe 25 degrees, I'm guessing. But as the revs increase past 1200-1300, it seems that the vacuum signal is lost and the timing drops back to 12 degrees, and the engine bogs right down. It does this with the old SCV and the new one that came with the carb kit. The car won't go over 20-25 mph depending on terrain. Could this be a clogged vacuum passage in the carb affecting the timing? It sometimes emits a whistling sound while trying to accelerate. I can't find any vacuum leaks. The engine idles properly and stalls immediately if I cover the carb throat. Any suggestions would be appreciated.