Hollow stem valves

[junior barns]

Originally Posted by Rob Wright

It matters a lot if you have a cam with "iffy" lift curves. You can easily lose 1,000 RPM of peak limiting speed by changing to solid stem from hollow in some combinations.

For heads popping off valves, I'll bet a hundred they had severe bounce at closing. That's generally what will make things break. Good thing some people test this stuff.

you mean too much seat pressure or not enough???