[Frank_Zeller]

this is a pretty good info.
http://www.sa-motorsports.com/diyport.htm

Best to just gasket match for the street and do bowl work (area under the valves) You will need to make sizing valves to use as templates. You mainly want to improve velocity.

Have done Pontiac heads see pics.
http://www.freephoto-i.net/users/Fra...t_port_ftz.jpg
http://www.freephoto-i.net/users/Fra...ber-far-LR.jpg
http://www.freephoto-i.net/users/Fra...rt_ftz_far.jpg