Removing intake manifold studs
 

OK who has the secret to removing frozen intake studs. I need to install the longer PMO studs for my carb conversion. I've been able to remove most, but have broken one so far and have four others that won't budge. They're soaking with PB blaster and have tried some heat (how much it OK)? Is it machine shop time?

They most likely have thread-locker on them and that needs to be softened with heat. Meaning: A small nozzle to concentrate the heat around (Not on) the stud.
Double-nut the stud, then apply heat around the stud and try to turn it with a wrench.
If the broken stud has no meat left, it is machine shop time because drilling it out by hand doesn't work very well.