Looking at the photo of the block the longer bracket would be needed if you had to use one, the oil pressure fitting may present a problem if the bracket were needed.

I have had success using a small pointed punch and a small hammer to turn broken studs and back them out. It sometimes takes a little work to get them to move but once moving it will unscrew. If the stud is bottomed hard into the hole this method will not work.

If you can get a drill into the area, center punch a hole as close to the center as possible and using left hand drill bits drill a hole all the way through. This relieves some of the pressure on the threads. Using the left hand drill bit I have had the bit grab the broken stud before it drilled through and screw the broken piece out. I have a Snap On set of left hand bits and start with the smallest size and work up.

I have a bother in law that used to break almost every bolt he tightened. I find it easier to fix his vehicles for him than removing the broken bolts

SUCCESS!  Thanks for all the input.  I was going to try the welding if all else failed and Anips suggestion was a good one, hire someone, not a time to learn on one's own.  Also I meant to say I was going to weld a nut to the stud not another bolt, for those interested there are many videos on you tube using this method one called "the right way to remove a broken bolt" where they start by welding a washer to the stud, then a nut to the washer.  however all the videos show this being done on a nice flat surface, not vertically under a car! HOWEVER, thanks to Joel's suggestion I used a dremel tool with a cut off disc and cut a slot into the bolt and it came right out with a screwdriver.  Yes I cut into the block a bit but I ground the edge down a bit and will add a washer to the stud to make up for it. Joel there was a broken drill bit it there but i was able to drill it out and then cut the slot.  I'm not sure I'm allowed to say where I got the part that broke, but it is one of the major Corvette reproduction supply houses that I have been a loyal customer of for years (not a C3R sponsor either).  Sent them an email and included a picture of the broken part days ago, still no reply! Philip thanks for the info on the left handed bits (Snap-on)  I have not been able to find them anywhere, good to keep in the toolbox!  ANYWAY THANKS EVERYONE THIS IS WHAT MAKES C3R SO GREAT!

Mario, I'm SOOOOOOOOOOOOO glad that you worked things out. Way to go!

  

Very good news, now get back to the great summer cruises.

Great news!

Hey, my Dad grew up in Hillsborough!

Jim

Jim, Small world, how did he wind up clear across the country?

This is why I love this Forum !

WWII.  His National Guard unit was mobilized and 5 years later he was discharged in San Pedro, CA from the US Army.