The holes are a standard small freeze plug for US cars. It's tough to tell if that kit supplies the correct size. It might be easier to get them from a Pontiac specialty engine builder like Butler, Spotts or BOP Engineering, or a Pontiac parts house like Ames.
Thanks for the reply, I had a look at Ames and found they do a freeze plug set just for Pontiac heads will this do?
FN765B Cylinder Head Freeze Plug Set, All Pont V8(RP) 6.00/set
67 Firebird 350, TH350 auto Convertible, B&M 3000 TC, 4bbl Edelbrock Performer carb and intake Black Jack headers,disc brake conversion. 10 bolt chevy axle with 3.73's and B&M Rachet shifter.
