I have
one Vortec water pump. Compared to the TBI pump, the pulley is in a slightly different position. Pulley alignment will be a problem. If there are other applications that are more-compatible, I don't know about them.
The Vortec pump also doesn't seal the coolant bypass hole in the block. Not a problem with Vortec heads, but TBI heads will flow coolant onto the ground.
Either you plug the bypass hole in the block, and use the Vortec pump with Vortec accessories,
and the Vortec bypass system; or you use the TBI pump with the TBI bypass, and hope you can get the belt alignment correct.
Photo 1. TBI water pump gasket surfaces
http://hbassociates.us/Chevy_5.7L_WaterPump_01.jpg
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Photo 2. Vortec water pump gasket surfaces
http://hbassociates.us/Chevy_5.7L_WaterPump_02.jpg
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Photo 3. Vortec vs. TBI pulley differences
http://hbassociates.us/Chevy_5.7L_WaterPump_03.jpg
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