Thanks for the suggestions, I still have to figure out what axle and spring layout would be close to the M101A2, Blazer, 2500 Chev PU, Dodge Ram????? so Hellwig can send something that will fit.
I would look at the pre-2005 Toyota helper springs. That should get you real close to the correct width/length dimension for the M101 main leaf.
These would probably work:
Toyota Helper Springs - 1972-2004 Toyota Pickup & Tacoma 2wd - 1500 lbs helper springs
personally not a big fan of the clamp-on helper springs - on all the trucks I have seen them on, they put more wear on the springs at the contact points then I would be willing to live with.
If you could score some Jeep CJ-7 front springs for cheap to free, it would be super easy to mix in some extra leafs to beef up the pack. I have done that more than a few times for low buck lifts and/or additional strength. A new spring center bolt, some C-clamps, a couple of minutes worth of work and Bob's your Uncle.
No other common vehicle that I can think of has 2" wide springs - IH Scout perhaps but those are getting sort of rare. Toyotas were close to 2.25 (metric) and everything else I am aware of is either 2.5" or 3" wide. Standard old trailer junk is of course 1.75" as is the M416 trailer setup.
I have no idea about the M105 spring width. I betcha someone could spare a few leafs out of those extra stout packs and not even miss them!