Why not just measure the spring length and (somehow) determine the load capacity then buy a common spring of those specs?

Like a double eye, 36", 1500 lb spring.

Does anyone have an intake manifold available? I have a 1951 288. I believe the part number is 426437.

https://packardinfo.com/xoops/html/modules/partslist/index.php?mode=partnumber&SearchValue=426437&ButtonLookup=Go

I was thinking of using a 12V positive ground alternator, 2 6V batteries in series and simply placing the cranking cable on the middle posts.

12V for an AC.

Does anyone have a source for these?

I'm looking for comments, recommendations, procedures and kits for this conversion. I would like to eventually add an aftermarket AC. My current status (pardon) is that my voltage regulator (6V) has failed again and so has my battery. For one thing, will I need a different starter?

Does anyone have a source or part number for a 1951 200 288 Battery/Oil Indicator socket? 2-wire BA15S type.

Thanks for your input. I looked at both links. The Dennis Carpenter link identified "Ford Truck F100/750 6 Volt 1948-55". I went to the O'Reilly's website and looked for 1955 F100 blower motor. They have the "Murray Climate Control Blower Motor - 35512" for $50.99. I purchased it with overnight delivery and installed it. Perfect fit.

https://www.oreillyauto.com/detail/c/murray-climate-control/lighting---electrical/motors---actuators/blower-motor/0da7cd2eedaa/murray-climate-control-blower-motor/mry0/35512/v/a/138261/automotive-truck-1955-ford-f-100?q=blower+motor&pos=0

Has anyone identified equivalent or substitute motors?

2-5/16" stud spacing (fixed)
5/16" shaft diameter (can use 1/4" with adapter)
1-1/2" shaft length (can use approximately 1-1/4" to 1-3/4")

6-volt

I think 12V may draw too much current. Thoughts?

Can someone provide a procedure or link for a description of how to remove this?

My operating temp is just above cold. I bought a thermostat and removed the flange/housing. There was no thermostat. The new thermostat needs a part to hold it in place otherwise I must have the wrong flange/housing or thermostat. What am I missing?