I'd like to know what it costs to convert from press-in to screw-in studs (vortec heads).

 

look in the yellow pages for automotive machine shop and call a few in your area, prices are a lot differant in differant parts of the country. around here it's around 5 dollars a hole, plus the cost of the studs. i do mine own and save a few bucks. k line among otherts will sell you the tools to do it with but if you're only doing one set of heads it may not be cost effective.

 

Studs themselves are about a buck apiece. Installation is "free" if you have the tools.

If you plan to use self-aligning rockers, you CAN replace studs with the heads on the car. This might give you an idea:

Rocker Stud Replacement.pdf