I'm not sure if Tecumseh ever made a lighted iron wheel for the HS engines.
They did, in 1973 the HS40's and 50's were the first to get the square shroud conversions with the steel flywheels you can find them on the Rupp Roadster 2's 73-75
you can see the differences between the '71 swinger and 75 roadster 2 I had earlier this year:
These steel Flywheels break the magnets loose pretty easy on a 30-40 year old abused engine so its a good idea if you are going to "go through" one do a little tapping and prying on the magnets and the spacers when you have it apart for service.
The smaller bore engines (with the different taper cranks) held out on the curved top design into 1974/75 but they quit using the ID tag, changed the throttle control, and stamped the number on the top of the shroud but the AL flywheels were still being used, of course at that point "mini bikes" were dead and just about anything that was running Lights was going to be a bigger bike to compete with the mini trails and spoke wheels so they got at least a 4 hp.
now that were are off track....the to original poster are you looking for info on an H40 or HS40, as they are 2 totally different sized engines!!!