Jay, here is the long version for both the 250 and 292 tests. There were over 200 tests conducted with both engines and not all of the results are discussed in the posts for the reasons mentioned in them, but what you are asking was tested. The gains from installing larger valves with the bolt bosses remaining intact are still gains none the less, but not as much as from removing the bosses entirely or by adding lumps. But you might see it mentioned in the posts. Tom can tell you if you still need that info though. Also, the long awaited printed and published version of these tests is arriving soon.
