just remember it's probably been in there for thirty years....give it a good soaking with WD40 etc and let it sit. The one on my notch took some getting out.
I ended up getting a small plumbers style propane torch and applying a bit of gentle heat keeping in mind there are rubber bushes in there from memory.(keep a fire ext. handy) you need plenty of leverage. smacking it with a hammer will just end up rounding out the inhex head.

[ Edited on 22-3-2006 by Stanley ]

on my 71 and 74 supers those bolts had 3 slots in the head which was supposed have the surrounding metal peened into them to stop them backing out
this maybe something to check

hth
Joel

Hi

Be very careful that you dont move the car off the stands when trying to undo them.

Steve

If Wd40 doesn't loosen it, try eucalyptus oil. It's the best penetrating oil that you can get.

or lanolin. It took me 2 weeks to get mine out the first time. drenching them with wd40 everyday. then used a breaker bar with extension, with gentle taps from the hammer.