To get some ideas on what it could be, I shot this video.

I literally started the car up yesterday, took it for a drive, got on the highway, and when I got off the highway, it started running like this. Since the rebuild in Sept, the engine has run beautiful. I recently took it to Pensacola, and it ran beautifully. I don't know where this miss comes from. The vacuum gauge jumping like that is brand new. This engine normally pulls about 19in of vacuum steadily. My books say that the sudden rhythmic drop of 3 points or so is most likely an ignition malfunction, but I'm not so sure. It's definitely not any crossed wires or anything like that. It literally started running like that when I exited the highway.

I tried the test where you pull plug wires, and it still runs like that. I'm just hoping it's not a valvetrain issue. The heads are reworked #7 heads, cleaned and machined back in sept with the rest of the engine rebuild.

I'm hoping the video might provide some insight. Any advice would be appreciated.

http://s22.photobucket.com/user/arro..._7571.mp4.html

 

Are your plug wires good , have you checked the plugs is the dist. Good no carbon tracking stuff like that. I had an erratic idle which I though was the cam lope . Turns out it was a vacuum leak . oddly enough did not affect brakes just idle quality. I plugged the hole on the carb mounting pad whic on some edlebrocks runs into the plenum and the idle was like stock lol. Just some things to consider.

 

I'm assuming plugs and wires are all still good. They're brand new! Lol.