That is an AFR gauge that I used to dial in both the idle air mixture and jets. I also balance the carbs with an airflow snail. The engine is the larger one ( 2165 I think ) that makes 180hp. It is a four lug and has four wheel disc brakes. The weather is almost nice enough in Wyoming to get it out of storage so I'll be re-listing it soon. I just need the DMV to open now for updated registration.