broken valve springs

That cam is not really a street friendly cam based on that lift and duration. Street driving something like that is going to wear out ANY spring on the market quickly.
If it was mine, with that much cam I'd only run a PAC spring and give them all the info on the cam, rpm range, etc....I'm thinking seat pressure should be closer to 300lbs. and open is about right. Also, what lash are you using?

thanks brian...i dont mind wearing out springs, i just dont want them to break into pieces. i use .025" for the lash.

should i be using a drag or endurance spring?