Freeze plug size for het cross over

Does anyone know the exzact size freeze plug for the heat cross over passages on '70 heads? I bought 3/4 and tried to squeeze em in but they were too big. Thanks~ Vinny

 

8MM, if it was like mine.

 

1970 455 buick heads take 18mm cup plugs.

 

Thanks for the help guys, but whos right?o No: I want to pick up the plugs tomarrow to finish the motor and i dont want to go back n forth to the store, ya know. Thanks again:TU: ou:

 

Greg is correct.......


not that I don't trust John:laugh:

 

Thanks!!!!:TU: :beer

 

Typing error. I left out the 1. Sorry.

 

Thats fine John, Thanks alot guys i bought the 18mm plugs and they worked perfect! AWSOME!:TU: :beer