A little late, but worth while information on gasket selection on the 4.3L.
The FEL-PRO Part # MS98002T is a great gasket set. But if one is new at replacing LIM gasket and is not proficient with a torque wrench, the VICTOR REINZ Part # MIS16168 is a great choice because it has a built in overtorque protection feature. I have both of them and both are great choices.
Two other items one may need, black RTV, the gasket kits typically include this but not enough for a backyard mechanic, and replacement bolt set, if the manifold gasket failed, the bolts likely are in bad shape and will be labor intensive to try and clean. Bolt set is FEL-PRO Part # ES72224.
2001 Bonneville SSEi, 219,000 miles.
Whats in my driveway:
1998 Chevy S10 4x4 ZR2, 1999 Olds Bravada, 2001 Pontiac Bonneville SSEi, 2007 Ford F-350 regular cab 2WD, 2008 BMW 335i coupe (Wife'* replacement for her Bonneville). The Bonneville is my favorite of all the cars in the driveway.