If nothing else appears to be wrong inside,I have another v.b. in the original small block 727 I could try.Or I could buy an aftermarket. It made the same groan with both the high pressure spring and the stock one. The manual called for 54-60 p.s.i.@1K r.p.m. in drive(on stands) and 90-96 with the throttle lever fully depressed. With the high pressure spring it had 110&140 and with the stock spring it had 65&100.A little high but not too far above spec. Why would the valve suddenly start moaning though?