D7-17a starter conversion

Takes the aftermarket oversize adapter drive end housing, same as used on D8 and D9
 [attachment=73373]D7-17A Direct Conv #3 (copy).JPG[/attachment]

Now I also here somethin about and oil seal and long nose and short nose . I ordered a 50mt starter but it had the left hand helical drive 11 tooth on it . So now I have located a right hand 12 tooth helical drive for it but they asked if it was long or short?

Long nose applies to the original starters. Conversion starters use the short nose (shorter vs long armature) and same RH helical drive used on D2,4,6,8,9 starters. LH helical drives are hard to come by and used on buzz bomb pony conversions D4,D6.
You need the current conversion drive end housing sold under the 371-12144 part number which are also somewhat hard to come by. Currently available on ebay at $160.
Side view should look like this when your done...
 [attachment=73374]D7-17A Direct Conv #1 (copy).JPG[/attachment]

My starter does look like that except it has the left hand version of that drive. Is that a conversion for the generator in the picture what is required for that conversion if you don't mind me asking.

Please see pics attached.

Please see pics attached.

True would be a challenge. But I've learned from thirty years of machining anything can be done just about if you want to bad enough. Is the alternator setup in the picture 12v or 24v. I had been thinking about trying to convert a 24v alternator off a cat 920 and adapt the gear drive to it. Hadn't really looked to close just have some of those alternators handy.