my old monte carlo did that when the cat went bad and clogged up, i guess to much back pressure can cause that. it may not apply to you but i thought i would mention it
double check all your fuel stuff.??
edit: someone above mentioned a lean mixture, maybe you have an intake leak and your sucking in air that is not being accounted for
I suppose the timing could be off, but the car starts and idles. Although the idle is very high around 1200. Never was high before. I swear I put the distrubutor back in the way it came out so I'm not sure how the timing could be that far off...
carb spray or starter fluid. or you can take a spray bottle with water in it...it does the exact opposite and will bog the motor down instead of revving it up. id prefer the water method since you dont want to spray ether or whatever on a glowing red hot header.
you might as well not even try that. you know there is a leak somewhere. just make sure all the bolts are tightened and in the right order. replace gaskets if needed.
you said it idles at 1200 that's a good sign of running lean. Also every time you take your dizzy out you should hook the timing light up at least I do just to make sure but that dosn't sound like it's the problem.
Run a bead of clear rtv around the intake->head mating surface down around the intake->block surface and seal the intake to the motor. Dont remove the intake, just run it along the outside along the 2 surfaces. Then see what happens. This usually fixes it for me.
Also double check your oil. If the intake is leaking to atmosphere then it might not be properly seated and you may have coolant dripping into the lifter valley as well.
If it makes you feel better, took me 3 tries to get my edelbrock intake to seal up against my gt-40p irons. Finally I ran the RTV bead and no problems since.
Sounds like the intake gasket is blocking the water passage, keeping the coolant from flowing through the intake and making it hot. Double check it. Vacuum leaks will make it run like crap, but won't cause it to get that hot, that quick.