Ford Repair: car is running bad sounds sick(think its the intake), mustang mach 1, double pumper

Question
Specs

1973 Mustang Mach 1
351C 4V
Bored .30 over
4 Speed
Comp High Energy Cam (32-225-4)
Duration @ 0.006" 280 / 280 @ 0.050" 230 / 230 Lift .53 / .53 Lobe Separation 110
Edelbrock Torker 351 Intake
(Custom? How do i find out what brand?)Long Tube Headers
Holly 750 Double Pumper Carb
MSD Electronic Ignition
2 1/2 Inch Dual Exaust (Custom no bends, should I use a midpipe?)
Dual Flowmaster 40's mufflers
9 Inch Posi rear end
4.11 Gears

Went to take my lovely friend out for a ride yesterday and she sounded like she was dying! I checked everything I could think of, sounds like the timing is somehow off or its not getting enough gas. I checked the carb and its settings are fine. I was going to take it out around the streets to see how she runs but then I noticed that there was oil leaking from a intake screw!

http://www3.telus.net/public/supeg93/oil1.jpg
http://www3.telus.net/public/supeg93/oil2.jpg

It is the screw closest to where I put the screwdriver. Now I am scared to even take it out. Anyone know what could be the problem? This oil comming from intake screw really scared me!

Here is a video of the sound.

www3.telus.net/public/supeg93/problems.avi

Like I said she sounds very sick and never used to sound like that at idle.

Please help!

Answer
Mark-

  First let me say that this is the first time I've ever had someone give me picture and video links.  I bow to you, sir.  Based on the problems you described and the sound of the motor I'd say it's probably a vacuum problem...possibly related to the PCV valve/breather (whichever setup you're running) system.  A lot of time if a PCV valve/breather is clogged it will draw up oil into the intake and sometimes even into the air filter.  That would also be in line with the engine's movement (it looked like it was moving back and forth at the very start of the video).  The problem that also exist with vacuum problems on carbed cars is that, if you have vacuum secondaries, it can throw the carb off as well...mostly at higher rpm or when you get a little "spirited" with the throttle.  I'd change out your PCV valve or breather and, if that doesn't do the trick, hook a vacuum gauge up to the motor and see how much vacuum it's pulling.  Expect it to be a little lower than normal since that cam is a decent size, especially with a 110 lobe seperation angle.  Oh...and as for the headers...most companies will stamp their name somewhere on the header.  Short of that, it's hard to ID them.  Hope this helps.

Steve