Bad vibes.

I built the engine. Tore it down from the long block. Came out of a friends plumming van. I've went over every thing twice. All plugs look good, good compression, vacuum. That's the first thing we tried to eliminate. I have no problem checking it all again just incase I missed something. I'm afraid its going to take out the mains cause its bad. Friend said it ran good in the van, but this guy wouldn't know if it was running on 4 cyl. or 8 if you know what I mean.