Ford 289 Valves for /6 - what a deal!

Ramp speeds, especially closing ones can require more seat load, even without more net lift. I found out with much surprise recently, that the 26918 PAC Comp LS beehive cannot handle any .904"-specific aggressive solid profiles, or even .875"-ones for that matter. One would figure a spring for a roller cam with 1.7&1.8:1 rockers would do fine, not so. Spring rate is 373# on those btw....