I have an old stumpjumper from the early 90s and i need a headset with a 27mm crown race. I have used used the Tange Levin CDS on many of my road bike builds and love it for its value and quality. Is there any reason this wouldnt work on a threaded 1 inch steel mtb frameset? I figure i better ask before i order. the frame had an old grease guard headset on it but it is shot. I suppose one difference that could get me is stack height. ill try and measure the old greaseguard one to make sure it isnt shorter than the Tange Levin prior to ordering.

Other than that, is there any reason a tange levin wouldnt work for a mtb build? It is listed as a road headset which is why i ask.

Should work. Before MTBs evolved their own standards, there weren't "road" and "MTB" headsets, just "headsets."

that was my hope I ordered one. I love the tange levin. Great headset.

Actually, a needle bearing type headset might work best for ATB's as they can handle more impact loads/road shock, because of the way the needle bearings spread the loads better and stay in adjustment longer than most ball bearing type headsets.
you do not need to find Stronglight headsets to get needle bearing design with your headsets. There's one by Miche, called the Primato that sells for about one third the price of an NOS Stronglight A9...... Bought one for a project not too long ago for about 35 bucks!

The Miche Primato, as [MENTION=426321]Chombi1[/MENTION] suggests, you be good to consider, as would the IRD/Tange "Roller Drive" headset. I'm not sure if either of these is available in JIS dimensions, so the OP may have to get his frame and fork prepped to ISO dimensions first.