Replace original 1970 U20 valve springs or not?

[Acotyk]

I'm refreshing a 1970 U20 engine, that was sitting for the last 30 years. shows 72,000 miles on the ODO. Should I replace the valve springs in the head? Do the original springs fail if left compressed for years? Any history of such failures?

[Nissanman]

Hi Acotyk, the springs need to be checked using the appropriate compressor for static compression values as well as uniformity across all 8.
My G15 springs were sitting at various heights and compression was all over the place so they were replaced with a consistent set.
My guess is that they may well be some tired ones in your engine