Freeze plug size?

[73 Charger 440]

Hey guys,

I cant find the smaller freeze plugs that I knocked out of my heads, I saw one here in my room about a month ago but I was only able to find the old bigger size ones today (which I already have new ones of, but the auto parts store didnt have the smaller ones). I ordered a Freeze plug set for the 440 but it only comes with block freeze plugs... Anyone have the measurement of the small freeze plugs on the heads (on front and back)?

Thanks in advance.