What Year Did Tri Valley Machine Close Its' Doors ?

[davethewave]

I took my motor to these guys from the time they opened their shop in Pacheco, CA . up until they called it quits. Great guys , Good 'ol days. I'm trying to figure out how many seasons my motor has since the last rebuild which was done during the last days before they shut down.
I know it's time to freshen er up, just curious how far I let it go this time !