[25stevem]

You can not run a 670 head , or any 14 degree head on a 326 motor here are the pictures to prove that.

Also even as you can see in my other picture using a small valve 389 head no less your limited to about .440” lift depending on the head gasket used and the deck clearance the motor may have, that is unless you notch / chamfer the bore or go to a .040” over bore to get that intake valve to clear.