H-pipe help!!!

Hey guys,i soaked the bolts on my stock h pipe for a day before i tried to remove it.So yesterday i try to take the header to h-pipe bolts off and they wouldnt budge.What size bolts are on the stock h pipe??I got all the bolts except the ones that connect to the headers off.Any tips for removing the sstock h-pipe???
 
I believe the nuts are either 9/16 or 5/8. After 20+ years they're usually so rusted on there isn't hardly anything that will take them off. You may try a torch to heat the nuts. I was trashing my headers when I removed my stock h pipe so I just cut the studs in half with a dremel tool.
 
Buy an electric impact driver. I bought one from northern tools, chicago brand, orange in color, great for any nut or bolt on the car that won't loosen with a ratchet or wrench. Don't cut the studs because usually the stud will turn out with the nut frozen on the stud. If you can't get the nut or stud to turn out, cutting the stud will make it tougher to get the stud out after it has been cut. An impact driver will knock it loose.