What kind of heads do I have?

Hey guys so I have a 318 I’m gonna build and I was going to use a set of 360 heads and put some work into them but I was thinking I might as well spend some money on the stock 71 318 heads cause I heard they have a smaller combustion chamber. When I actually took a look at the heads it looks like they have 1.88 and 1.60 valves like the 360 heads and the valves match up perfectly to the 360 ones so have no idea what heads they are or which of the two I should use. The casting number is 3769974.