exhaust manifold question

Exhaust pipe broke off at the flange coming out of the exhaust manifold, thought i'd change everything instead of getting it welded (2000 silverado 1500 4WD). Rounded off one of the nuts on the passenger side, now it looks like i'm gonna have to pull the exhaust manifold off to get the nut off. Any tricks to getting the manifold off without snapping a bolt off? Or better yet...any tricks on getting the rounded nut off? No room up there to get a vice grip on it. Appreciate your input.

Northstar

Exhaust pipe broke off at the flange coming out of the exhaust manifold, thought i'd change everything instead of getting it welded (2000 silverado 1500 4WD). Rounded off one of the nuts on the passenger side, now it looks like i'm gonna have to pull the exhaust manifold off to get the nut off. Any tricks to getting the manifold off without snapping a bolt off? Or better yet...any tricks on getting the rounded nut off? No room up there to get a vice grip on it. Appreciate your input.

Northstar

with the engine hot/running , loosen each stud on manifold...

you will need new bolts...gaskets...and some medium lock tight you must torque the bolts to the correct sequence ...middle to outer bolts..

I forget what the torque spec is ..these bolts do break...just sitting there..common problem..

with the manifold off drill it out/ grind head off then drill...