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.