namm

I dont have a gramm scale and would love to know. I use to run stock valves with stock springs, cower retainers (87093) with Toda spec B. I ran this for over a year reving to 9000 rpm and I changed the valves to ferrea competition stainless steel and I droped a valve at 5000 rpm after a week of reving the motor to 9000. The valve broke 3mm below the grove at the top of the stem. My friends are thinking the valve had a defect. I am wondering if the valve is heavier and that might have caused the whole thing. By the way Toda spec B can be run with stock type R valve train, the manufacturer said so.