1969 #5 Head Rebuild

My 69 350 .030 over is on her way to life again. The only thing left now is the heads. Well I saw some replacement valves at Summit Racing. I don't live to far so I drove up there and bought them. Well they gave me the ones that they said would fit, but nope WAY to big. Does anyone know where I could find some valves for my application. Even somewhere where I could get them checked for length and width. The guys at summit didn't seem like they knew what they were doing. So I would like to go to a pro.