No, those are not screw-in studs. The "red loctite" you are seeing is sealer. The studs go into the water jacket, so sealer is a good precaution.
There are a couple of options for screw-in studs. If you wish to keep the rail rocker arms, not recommended, you can get a stud that has no hex, just a stop ring. Mr. Gasket used to supply these but don't know if they still do. the beauty of thsam was you onl had to tap the stud holes, not mill the stud bosses. My favourite is the 289 Hi-Po style stud. To install them you need to machine the pedestals down 0.230" and tap the holes 7/16-14 (UNC.). I would also suggest you intall the FRPP guide plates, and use either early 289 conventional rocker arms, or slightly better, mid '78 and up stamped steel rocker arms using modified sleds, or best of all aluminum roller rockers. Order custom length hardened pushrods to use with the guideplates.
Assuming you already have the heads disassembled and the studs pulled, you can machine your own stud bosses on a drill press using a counterbore cutter and pilot. Bolt your heads together, chamber side to chamber side so that the angle of one cancels out the angle of the other. This makes the stud bosses level with your drill press table. Set the depth stop on the drill press with a 1/4" piece of keystock. 0.250" is close enough to 0.230". Use the slowest speed on your drill press. Cast iron is best cut dry. Once the stud bosses are cut, use the drill press to ensure the holes are threaded straight. If anyone is interested, I can show a series of photos detailing the procedure, or will machine and tap them for you.
Last edited by PrecisionTrans; 04-08-2011 at 02:21 PM.