I have this engine that i bought thats been running real ruff, surging issues and idleing issues,its a 305 with a carb on it.its a 600 holley and i see where someone broke the egr valve off and blocked the opening with a screw.It is not leaking from the area but i was wanting to know if something on the inside of the valve is causeing these issues.I didnt want to take it apart if it wasn't leaking but i dont know if its opened or closed from what i have been googleing. thanks!