I have a ram 150 with a roller 318 and an rv cam from comp. It has a 4 barrel intake on it with a 600 4barrel edelbrock. For some reason when I hook up the advance line to my distributer it runs fine until I run it around 1000 rpm's and it'll miss and pop like crazy. But, when I run it above that range or ideling it does great. I have put a new distributer on it and it didn't help. Timing hasn't helped either... Any ideas? I have my vaccume line hooked to the small front left port of my carb...

 

I would suspect you have it hooked up to full time vacuum not to ported vacuum