err...Sarge, he's talking about an LS2 engine.  As in the all aluminum engine found under the hood of most C6 Vettes.  LOL.
I doubt any of the LS engine pans are an issue with our truck's generous room back there.  But the truck pans definitely fit.  And, as far as I know, the pans (truck, vette, f-body, gto) all interchange so long as you use the corresponding pickup tube.  Check with Capt on the manifolds.  I believe he is using '98 F-body manifolds.  But if you are already going to the expense of an LS2 engine, why not invest a little more in some nice S&P headers, which are specifically designed for this application.  With headers and a nelson tune you'll have an easy peasy 430+ hp on an otherwise stock motor....and have a silky smooth idle....and get excellent gas mileage (if you can manage to keep your foot out of it).  Man, I'm jealous.