1970 Heads

[bigdawg]

Hi,

I am trying to prove that I have 1970 Heads on my 390 with out taking anything apart. Someone told me that 1970 dog leg heads have 7/16 bolts. If that is true a 5/8 socket would fit on them. This holds is true on my heads. Do you know if 1969 and earlier heads have 9/16 heads on their 3/8 bolts?

Thanks
Bigdawg