Putter, Yes but you will need some clarification.
First off breakout your copy of Guy Fays Letter Series Originality Guide.
Chapter 9. Reference pp 103 LH. column gives you the linage of the M through the 400. Yes the M series culminates at the 400. crossing into the Number series. Stage I and Stage II Super M LPs used the Same cross wise tank like the one on that W6 at the bottom of pp 107
But when the Stage III, SM-TAs came along there was no plans to do LP, But as an after thought 500 were commissioned to be built,
Out-of-Shop,,,But still considered Factory!!!
It is at this point where things get sketchy. IH was notorious on keeping records, So most of the info that is out there has been gathered from old IH Mechanics, Shop Managers, Field Rep. Mechanics!
A tank manufacture got the go ahead. Lubbock and San Angelo tanks have a mono-Valve assembly @ the 11:00 position at the rear of the tank (as if you were sitting in the Operators seat) this Mono-valve assembly is a one piece unit welded into the tank,liquid, vapor, fill,vapor return. It is this tank that has become the Quintessential tank for a SM-TA.
There is not a series of valves welded into the length of the tank.
(Something like the tank pictured in Randy Leffingwell Book, Farmall Eight Decades of Innovations,, pp. 183)
So the tank maker in Lubbock and San Angelo Texas was charged with the task.
Tractors were just pulled out of the Assembly line and sent to Lubbock or San Angelo. the factory guys were simply looking for 2500, 5000 + ft piston assemblies for the build. There is, and was no Rhyme or Reason in Serial #s. at least to date.
Over time there has come to light, there were a handful of LP tank companies scattered out through the Deep South That did this conversion too. I do not know the particulars on those companies.
a Few Yrs ago I learned of an old man in NE Texas who was Authorized to DO Field conversion at the Farmers place. had a truck, tools tanks, carbs all hoses and hardware and Authorization from IH to do the work++++++++ re-stamp the Tag!!!! He had a little Black Book, ((Kinda like what most of us kept girls names and phone #s, & addresses in)) Except................
He had the farmers name, address, phone ++++ the Tractor serial#, and the Date!!and what was done!!!!!!!!!!!!!!
Bad news the old man died, Kids cleaned out his house and that little black book was lost!!
OK back to how it goes
Tractors were built at the Factory, minus Tankage, and Carbaration.Then shipped by flatcar to the LP tank factory. There the tractors were completed and sent on the the Dealers.
Then!! tanks and carbs and necessary hardware and hoses were set back to the factory so tractors could be completed there too! This is the whole story as I know it,. If you want to visit sometime my Phone # is (512)577-3837.
Hope this helps!