Ok with all this head and stroker talk I thought you all would enjoy watching some of these
vids by Richard Holderer. It is about head flow and dnyo testing about 30 or more heads . Some of the testing is old and some of the heads are not on the market anymore. A lot of the heads are aluminum so may not be of use to some of the guys here. It is a 4 part series but only 3 parts have been released. Hope some will learn from them. Wanted to add the there is no testing of early 289 heads .
https://www.youtube.com/watch?v=EWSlYvstFIU