I'm about to do a partial rebuild of my E88 260z and I was wondering what is your stance on replacing valve springs if the engine is internally stock well maintained.  I already plan on doing a full disassembly and inspection to the head components, but should I plan on replacing the valve springs as a matter of preventative maintenance or not?

Thanks

I'd have a machine shop test them for squareness and sag. I've read the exhaust go bad first.

From Tom monroe's book...

 

Is this book still available?

Amazon.com has it, $20.

Awesome... Thanks