1999 Honda Civic smoke / stuttering after head job

I cracked the head gasket about a year ago and just changed the gasket, put in a resurfaced head, and a new exhaust manifold (the hold one had a crack). I can start my car just fine, < 1 minute later smoke starts coming out of the where the exhaust and head meet. Its idling at 2000rpm's and when the smoke starts it will drop down like it wants to die, and then "violently" jump back up to 2000. The smoke isn't white, and it isn't thick, just a steady light smoke...