valvespring breakage blown promod

We've broken 2 exhaust springs on a KB/Olds blown promod. One was at idle when they were new..figured it was a flaw. After 7 passes with some tireshake another broke. We run psi/nextek style with 360-380lbs on the seat and 8800 rpm redline.14-71 hi helix 37 psi.
Should we trash the exhaust valve that had the broken spring on it? We changed the spring and put one more run on it without trouble. Our data logger broke so we don't know where in the run the spring broke.
These springs are made for a huge cam and we only have 840 lift so there is a big margin from coil bind..could this be pi$$ing them off?
Thanks, Mike

 

Where did the spring break? we run a similar spring in our hemi, They usually turn to junk after after 5 to 6 runs(service heads after every meet), we are uncertain when they loose pressure, could even be on inital start up!! We have got new on head tools to check them all the time now. We are alway breaking the tips of the springs, i can tell how hard the driver has spun it without the data logger by the broken spring tips

 

Try this: Roy Johnson told us to set up the springs to compress to within .060 to .100 of coil bind. This takes the side shake out of the springs. Ever have a carpenters saw vibrate and as you came closer to the handle the vibration got higher in frequency until it just stopped? That's what happens to your springs when they get to coil bind-----they stop vibrating sideways and settle down. It worked wonders for us. Try it and see if it doesn't help give better performance and longer spring life. Never leave the pushrods in the motor for longer than eight hours. Makes the pressure drop like a rock on the ones that stand open.