318/360 heads,with thumper cam

As for how far down the hole it looks like somewhere around, .050?so the notches in the pistons seem like overbore or no?imma get a digital one from harbor freight like mischeifdart said just to be sure.thanks for the help guys,do the heads need bigger valves,or are the stock ones good for street use.

Notches in the pistons are for orientation, facing front of the engine. I believe they are replacements and by your preliminary measurements may be .020 over......050 in the hole also looks like it could be a rebuilder type piston to me.