SBC Stamped ANDERSON RACING trying to find more information about who built this

So I am working on a 69 Chevelle for a customer and I am trying to figure out what this motor is, I know its a first Gen 350 4 bolt but the vin ID numbers are pretty much gone and stamped right next to them is ANDERSON RACING. I have reached out to a number of companies with that name and so far no match. I have no idea how long ago it was built and I haven't pulled the pan yet but under the valve covers it looks great and it runs great. All I know is that he bought the car from the east coast somewhere and had it shipped here to California. If anyone here is familiar with an Anderson Racing I'd appreciate the info. So far I have already talked to the one in Missouri and the one in Washington, plus a couple of others.