Soak it in Pb blaster first, for a while. Then notch the top with a dremel. Make the notch deep enough to get real good bite with a flat head. Before you try twisting it out, heat the head up with a torch to try and expand the mating surface. If you hit it with Pb blaster again after you heat it up, the thermal shock might help bust it loose too. Good luck with your project, take your time and take breaks if you start getting P.O.ed.

 

HAHA GOOD LUCK IF THE EXTRACTOR SNAPS. ur screwed and they do snap. and if its a flush mount stud thats broken off your not gonna get anything on it except a dremel or extractor, trust me the screw driver, wd40 and dremel idea is the best by far.....we do 4 or 5 of these jobs a day. 5.7 do it to on rams

 

I'm 6'5" so I have pretty big hands. 4x4s take a little more manuevering around than RWD. I know when I changed out Truck's 4x4 manifolds to Gibsons it took a little longer. I have yet to loose a broken bolt on a 4.7L. I use Alden prograbits and I've removed broken cam bearing bolts, exhast bolts etc.

 

those are probably alot better quality than mine, just imo try the dremel first, eleminates the possibilit of breaking a hardened bit in your head, ive done it in the block and in my experience its was very painfull

 

I have a few sets of extractors, each with at least 1 bit missing & they're missing because I snapped them. I tried the style of extractor shown above and did have some good results, but I found that with the smaller bolts like the 8mm one described here, there isn't much bolt to play with & if the remaining piece of bolt was stubborn, I'd end up pulling out a bit of the bolt center leaving me with a bigger problem. I developed a technique using a welder, washer, and a nut that has so far worked for me 100% - the heat and welding shrinkage has always broken the bolt loose. Here's a picture of one such bolt - it looks pretty rough because I found it outside when I was cleaning things up & decided to take a picture of it to add to my collection:

BoltRemoval-2.jpg

A lot of people I know use only the nut and weld through the hole in the nut to the bolt, but I find that in close quarters it's a lot easier to hold the washer to the bolt with a magnet and weld that to the bolt and then to add the washer and weld on the outside of the nut to hold it to the washer - this way, they always hold & the bond is strong enough to remove the errant bolt.

 

where there is a will there is a way, being that most of those heads for the 4.7 are aluminum you should have a failry simple time getting a ground on the bolt?