How long can valve springs stay compressed?

I have a engine, 350 small block, that I put together for my truck.It has a 280h Comp Cam Kit,cam,lifters,springs,locks,etc.The engine ran good for about 2500 miles.I pulled it and it has sat for about 3-4 years. I did loosen all the roller rockers though, untill all valves were seated,and then some.So the springs are not really fully compressed ,but holding the valve shut.Are the springs still in good condition after staying in this position after so long?:confused:

yes. they will be ok. heat and cycles mass lack of oil to cool them and runing them down to coil bind kills springs. sitting in a installed height they should be ok. i would put some oil up there before you start it and do not run it at hi rpm till springs are broke in .to do this you want to run it at low rpms and let the engine get warm and let it cool off do this 3 to 4 times .i do this all the time i think it helps