340 valvetrain help

Don't have many details about the engine. It has been through a few hands and the info I got was very limited.
Its a 340 with the original heads. Not sure if the seats have been changed out. It has a performance cam but im not sure on any specifics. Don't know what kind of lifters.
The distributor doesn't have any vaccum advance. Has your basic holley 4 barrel double pumper. Not even sure if its a 600, 650 or what.