My rule of thumb is if it's running and roadable, it's worth $500 and anything above that is dependant on all sorts of moving target variables. You live in the heart of aging hippie land so old Volvos might go high or maybe there is a glut of them on the market for the same reason.

My other rule applies to non-runners. Never count on it being worth more than the value of entertainment and satisfaction from bringing a machine back to life. I try not to buy or even accept one as a gift unless I'm prepared to sell my current ride and drive the new project long enough to spread the losses over an extended period. They almost always end up taking so many nickel and dime items that they cost hundreds more than you will get out of them. That doesn't make a project a bad idea, just you have to do it because you want to, not to make a profit.

That said, you might get a tank for $50 and new filters, a rotor and cap and plugs for another $50 and be on your way. Sell it for $500 and you have $250 profit.

Mel