Turbine Doc
Just Another Diesel Guy
Opinion eh, well for what it's worth I'm thinking it should probably remain in the zone GM put it at, sort of like a ducted fan where too much either way is a bad thing, the shroud was spaced to allow proper negative pressure area on back side of the condenser/rad when clutch was disengaged and you would have adequate flow of air supplied as vehicle went into the wind, my fear would be you might get improved flow when fan is moved closer or further away from heat exchangers, but would change flow characteristics when clutch is not locked up fully and your "slippage flow" with disengaged clutch won't be correct.
As I typed another consideration came to mind, you have a rotating mass (fan/clutch) and semi balanced assembly intended to be X distance from pump/mounting boss, going longer you've changed that geometry/loading factor possibly putting extra load on the pump shaft/bearing, not saying it won't work, just more to the thought process than just location of the fan, probably needs to be "modeled" to know what the right answer is, me I probably would not do it, or not do it without a backup plan if something went bad, I'd know the answer before going on a long trip or towing a load of any significance.
As I typed another consideration came to mind, you have a rotating mass (fan/clutch) and semi balanced assembly intended to be X distance from pump/mounting boss, going longer you've changed that geometry/loading factor possibly putting extra load on the pump shaft/bearing, not saying it won't work, just more to the thought process than just location of the fan, probably needs to be "modeled" to know what the right answer is, me I probably would not do it, or not do it without a backup plan if something went bad, I'd know the answer before going on a long trip or towing a load of any significance.