pressed in..
there are both screw in and press in studs on 350s. it depends on application. i will say that fatory heads are most likely press in. high performance applications may be screw in.
No you can get screw in studs mainly for high performance engines.
They are pressed in.
Around 450, to 460, lift, 250, to 260 degrees duration, 116, centerline. New answer: If you run anything bigger then a 400 Lift, Then you MUST change the rocker arms to a LONG SLOT rocker arm are you will CUT the rocker arm studs in half. Even with the 400 LIFT it will still try and probley pull the rocker arm studs out of the head if the studs are pressed in like MOST stock heads are.
you have to remove the pressed in studs ,and tap the hole with the proper thread size for the threaded stud. this may require drilling the heads with the proper size drill, for the tap size you need. you must make sure that the new threaded studs are bigger than the pressed in ones, or you won't be able to thread the stud holes.
The press-in studs are on the cylinder heads. That's where the rocker arms go. Press-in studs don't stay in very well in high performance applications, so most people either have there heads machined to accept screw-in studs, or buy heads that came with screw-in studs. A low-cost alternative to screw-in studs is to have the press-in studs cross drilled to accept roll pins to keep them from pulling out of the pedestals. This only applies to iron heads, as aluminum heads always come with screw-in studs.
350's use rocker studs instead of bolts, and they are mounted to the heads.
Unless some one has replaced them with aftermarket studs their more than likely 3/8
if you can remove the broken studs without doing damage, you may be able to redrill the holes with the proper tap drill, and retap the hole for the screw in studs without removing the heads. careful you don't drill through the head, and get drill chips in the engine. i guess it depends on how good you do machine work.
There probably "pressed in" so take a couple of old nuts or balls from the rocker arm, put the nuts on the shaft, then put the rocker nut on and just tighten it up, it willl pull the shaft out of the head. Good Luck
Anything over 400 lift , you will start having problems. Pulling studs out of heads, coil spring bind, rocker arm problems. Ect...