You can’t have too big a supply if running a pump that large and only making 500hp. You can have too small a return though. Make sure as **** not to restrict the inlet of the pump and make sure as **** it’s gravity fed at all times (read: mount below tank level and fed from a baffled sump). Those are keys to making a big electric live a long happy life. I’d run -10 the whole way from tank to regulator and 2 -8s from reg to carb. And I’d run a -8 return. My 2 cents.