I have 390 FE with a crane cam in my 66. When we rebuilt the engine, we put the cam 180* out (I wasn't there when this happened). It is becoming a pain timing it by ear and driveablity. I would like to know how far apart the timing marks are so I can remark them, if anyone knows. And once I have marks, where should I have the timing set at. Im at sea level here in California. Im pretty mechanicly incline so to be honest I dont need a full page telling me how to do this....just the measures inbetween the marks.

 

It's 5/8" on the damper between zero to ten degrees and so on. Initial timing will depend on compression, advance curve, type of fuel, etc. You should be able to run between 8 and 12 degrees.