Alright, Team I got this finally resolved and she is back on the road. The fan shroud does rest against the end tanks of the DeWitts radiator. The spacers worked as intended when the upper shroud was as placed over the radiator. Had to trim the cushions inside slightly. I would never expect anyone to follow in my footsteps on this procedure, but despite the amount of down time, I am happy with the results.
So here is a checklist for any owners brave enough to do their own heater hose nipple replacement in the future.
The old plastic retainers will be done for, you will need new ones for the press on fittings that connect to the housing. Jerrys replacement heater hose fitting comes with a retainer , however the other hose will need a replacement. You will need Dorman 800-407. It contains the retainer you need plus you end up with a spare heater hose fitting retainer.
There is a good chance your heater hose fitting will snap off close to flush with the housing. A special large size EZ out might do it but most likely will not. The pot metal will shred up before the corroded threads seized in the housing let go, that is what happened to me. I then used a 7/8 reamer drill bit to slowly eat away at the snapped off fitting. When I say slowly, hours of letting the bit eat a little into the fitting and visually checking the progress. Housing needs to be in a vice and be very careful not to clamp onto a section of the housing that compromises the bolts and connection containing the thermostat and seal.
Jerrys suggestion on the punch was spot on. It helped remove a good portion of material that could not be removed by the reamer because it was too far down in the housing. It takes a while though, pack your patience. You will need a thread tap 1/2-14 NPT to chase the housing threads and knock out any remaining material lodged in the threads you cannot reach with a punch. Go slow and take the tap out often to visually check threads are being cleaned off.
The fans I used are 12 inch spals. You can get them from summit part number SPU-IX-30103202.
https://www.summitracing.com/parts/s...SABEgLmiPD_BwE
About $500 for two including tax. They will need to be trimmed to fit. The passenger side will require a significant amount of trimming, including removal of one of the support fins to clear the accumulator and its bracket. The fan side closest to the thermostat housing will need to some clearance to fit around the housing. Yes, these fans are huge. Together they both move about 3800 cfm of air and I believe it, even with the curved blades they are loud. They are not on for very long either.
Overall, I would recommend just getting the DeWitts shroud for about the same amount of money as it is direct fit. If you like trimming and custom brackets, the extra 1000 worth of cfm the summit spals flow over the DeWitts drop in unit is a nice reward. You do not need it, but it was fun to make them fit. I ended up needing to re-pin the connector off the spals to new 12 gauge plugs to fit the factory female plugs. These work:
https://www.racetronix.biz/p/connect...-2f-2m/rcs-011
The Summit Spal wiring will need to be swapped to match the factory wiring flow for positive to ground, otherwise the spals will push air instead of pulling as intended. Red wire off the spall needs to connect to the black w red tracer wire on the factory connections.
TLDR; Take your thermostat housing to a machine shop for R&R