A tuliped valve is just what it sounds like, it's dished concave in the center to make it lighter, but they're not used too much any more with titanium readly avaible. They actually look like a tulip or morning glory flower and add a little to the combustion volume. They were real popular in the old days on sm/blk chevies, when we didn't have oll the good valve springs that we do today when the only roller cam manufacturer was Chet Herbert, and Isky was only making flat tappet cams. I'm talking mid 60's.
Zip.