Need help changing Cat Converter

Currently changing my catalytic converter on my 99 jimmy. having trouble with breaking the top bolt on the flange closet to the engine.....any suggestions?

Get some good penetrating oil from the auto parts store, (WD-40 won't do it) spray it up real good every 2-hrs and let it soak overnight.

The issue isn't so much with breaking the bolt, as it is with the location. no room for sockets, or open ended wrench. you can tell they put it together while the body was off the frame....just wondered if i need to torch it off

Got to the nut and bolt with a 2 foot extension

good luck changing that conveter .;I took mines out today and it took me 7 hours,in my drive way first I rounded of the nut on top with a big drive 15 and a long exstention then i tryed every trick in the book to to get it off ecept useing a blow torch,and in the end i had to go to home depo to get some acksaw blade, i got mad at the nut and cut it into tiny pieces I showed it who was the boss after it kicked my but for seven hours it was quite an exsperienc i tell you