Push Rod Lenght

I am building a 1966 389. All the numbers as far as I can tel indicate that this is a 66 389.
I am putting in the equivalent of the Ram Air cam.
I do not have any of the old push rods however. The "stock" push rod is 8.625. This doesn't take up the slack in the valve train.
Does a 66 GTO motor use a different lenght push rod?
I found a 2nd design push rod for a 67 400 motor that is 9.132 in length. This does seen to work.
Does any body know about this.
Thank you for your help.
Dvid Randall

David, first off i would worry and the pressed in rosker studs in your 66 heads if your going to a RA cam with high rpm's . With that high of a lift and the age(if they're old) of the pressed in studs they may end up breaking. As for the pushrod lenght.... that would depend on what year RA cam your wanting to use and if your going to be using 1.5 or 1.65 rocker arms... Joe