The 1996 and later engines have the "Vortec" heads even though all the engines were called Vortec. The key is the heads and intake as the block is the same for all post 92 (balance shaft). I would stick to 2000 or newer myself.
I have seen a few engines that have a mini LT1 style intake manifold (aftermarket), this is a highly sought after piece for its uniqueness
The Marine EFI intake has the largest throttle body available which is slightly larger than the LU3 throttle on the Vin "X" engines starting in 2002.
Another thought is the 4200 "Atlas" engine from the trailblazer since you are willing to keep the engine EFI
Since you also hail from WI, head over to Gibsons salvage in Menasha for the best price that I know of in East Central WI for engines, etc.
Scott
