See, I've known this was a problem for a while, and I did some research on finding a fan that had a longer connector nut or protrusion of some type (where it attaches on to the water pump pulley). I've been told if you can find the clutch of a Kodiak or Topkick that it has a 2 inch long "Nut" and it pushes the fan forward but I am not sure on the years and it's not easy looking up parts for them because they are usually service vehicles and not real available on places like rockauto or what not.
There is a ford part I have found that has a longer extension but it requires some trimming and fitting of the fan assembly which I have not done yet. I figure you have to be careful with the cutting and stuff because it will affect the balance, and I have not quite crossed that bridge yet. I did not think about it at the time but it's probably possible to use the fan off the original ford assembly and that would work as well. The Hayden part # is Hayden Automotive 2789. I found a great resource on their website for looking at the dimensions of their various fans and combined with RockAuto.com you can look up the part # and then they have a link at all vehicles that the fan clutch is used on and go from their to look at a fan. I'll probably do that right now in fact and next time I get a chance to go to the salvage yard find my new discounted fan, lol..... It is a reverse rotation fan clutch, as required by the LS motor.
Alternatively you could probably just get some thin ABS and cut a loop of it long enough to go around the outside of the fan shroud and wide enough to get it pushed in further and then rivet it to the shroud but I am still not sure if it would draw enough air that way.
Hayden 2789 Fan -
https://www.amazon.com/gp/product/B000C39C1I/
One other thing to make sure of in case you try it, if you bypass the heater outlets you must have the inlet and outlet connected together. ICT makes a small bypass hose that I think is 5 bucks but in a pinch you can just use a heater hose loop long enough to not kink. If you are hooking up your heater hose already and need a way to hook up your steam pipe you can use the adapter below that is made to go in the heater hose (I believe it goes into the return pipe OEM but you might want to verify the exact pipe). If anyone has told you it isn't needed then they have misinformed you.
ICT LS bypass hose -
https://www.amazon.com/dp/B013QNJ9SQ/
Four seasons heater T fitting -
https://www.amazon.com/dp/B000DELVTC/
Another factor you may run into is overheating, even with a 4 core old style radiator. Some guys have problems, an I assume it's because their radiator is old and has not been cleaned. and then again even with a 4 core setup cleaned others have had issues. It seems the older radiators just do not flow quite as well as some of the newer ones. As such most of the guys that have done swaps end up swapping in the an OEM style radiator out of the newer trucks. It is a direct fit unit that drops right on the rubber mounting pads and then you either need to use the big block radiator top plate or use some sheetmetal and fabricate your own version. I'm probably just going to make mine out of aluminum unless I decide to go with E-fans.
Spectra CU730 Rad -
https://www.amazon.com/gp/product/B000C7TVYM/
You may have considered these things already but if not hopefully this will help add some detail.
