A Sherlock Holmes needed to ID 340 springs - Aftermarket

Springs are so cheap. Just buy the right ones for your new cam and be done with it. That's the only way to be safe.

X2 or.......if you wanna be real stubborn, take them to a machine shop and have them "rate" them for you. That still doesn't tell you anything about how many cycles they have been through however. Id throw those in the trash and buy whatever springs my new cam required if it were me.