If you remove the front engine mount remember to support the engine. The gm service site recomends an exotic engine support but mentions a floor jack will do. They dont mention if this work either?
I also looked up how to remove the rear (right) exhaust manifold here it is.
1. Remove the EGR inlet pipe from the exhaust manifold.
2. Remove the EGR mounting bracket bolts.
3. Remove the EGR mounting bracket.
4. Remove the heated oxygen sensor lead.
5. Remove the fuel injector sight shield mounting bracket nuts.
6. Remove the fuel injector sight shield mounting bracket.
7. Remove the right engine lift hook nut and bolt.
8. Remove the right engine lift hook.
9. Remove the exhaust manifold studs.
10. Remove the exhaust manifold.
11. Remove the exhaust manifold gasket.