#4 would be the one. What am trying to determine is the length that would correspond and add to the total runner length of the engine (intake manifold runner length + port length). Do you happen to have this info or something close?You probably have no answers because there are multiple ways to express it.
Group "A" answers for exhaust port, Group "B" for intake port. Within each group, broken down as follows:
1. The distance from the nearest valve edge to the face where the intake/exhaust manifold bolts up.
2. The distance from the furthest valve edge to the face where the intake/exhaust manifold bolts up.
3. The distance from the middle of the valve stem to the face where the intake/exhaust manifold bolts up.
4. The "effective distance" which allows for the curved tract path and non-laminar flow applied against the average of the multiple distances and paths.
1 through 3 can be determined via a tape measure. Number 4 is best measured with real data, or alternatively, by acoustical methods. All of the answers do have relevance and meaning, however, number 4 is probably the most useful.