Magneto 610906 replacement

Looking for other options for a replacement magneto coil, it's off a 1970's Craftsman lawn tractor, but believe it's a Tecumseh part. The tractor manual says p/n 610906.  All I've seen are 'Discontinued, no longer available', or E-bay choices that probably don't work.  Anyone aware of substitutes, or do I have a new boat anchor?

Thanks for the reply:  The stamped numbers on the engine cowl are 143-672022 ser 7055E.  The tractor model is 917.253150.  I hope you don't need more info, it's at a relative's house, a 3 hour drive away!!  He saved the orig-o owner's manual, and I believe he bought it around 1975 or so.  It's a Craftsman machine, and the manual diagram has the subject part #.  He has an old receipt from Sears for an identical coil he replaced before, their complete part # was 71-143-610906, which he bought in 2005 from a local Sears outlet (back in the day when they were still in business).  I'm sure the unit is faulty, no spark at the plug end (with screwdriver stuck in there, spin the engine), pickup surfaces clean and gapped to about 8 thou, grounds intact, no 'kill switch' affecting it.  
  I realize they don't make this anymore, and it appears only old used parts pulled off another carcass are for sale, but I was curious if anybody out there has discovered that, say, a magneto part #XXXXX off a Troy-Built will fit if another mounting hole is drilled, or something creative like that.....I've tried (in the past) taking failed magneto-coils apart to see if I could fix them somehow, but end up destroying them even further in the process./Scott

Thanks again for the reply.  Yep, I saw that HH120 designation in a cross-reference for Tecumseh engine numbers somewhere, but that lead me to the same dead-end.  I may have given myself an idea, by adapting another coil to the motor.  I don't know how a magneto coil is 'rated', and I've seen the figure of 20 amps tossed around...but I'll start with a mag-coil unit that's close to the displacement of the older motor.  Sounds like fun!!  Thanks again/Scott