I just installed a indy crate engine 500 wedge for a friend of mine at low rpms it run rough and will not idle.When i rev the engine it slow about returning to lower rpms. It revs quick i don't think it is fuel problem i have changed the carb and it still the same.It came complete carb,dist, every thing was set on dyno ? it has a chrysler dist. I tried to call Indy twice but they pass me off afew times and then they say they will call me back.I would like some advice where to start troubleshooting at . like i said i have already swap card and checked air gap in dist. checked orange box and made sure of good gound . i have not moved timing i checked it at 2000 rpms and it checked out to be 38o any advice would be welcome.