185's 649 starter on a 433?

I have a 433I that I wanted to upgrade starter on to help it turn over faster for easier starts.  When I asked my AGCO parts man about using a Iskra type (japanese) starter for this, he said that I should try taking a AC 185's 649 starter and swapping into the 433I engine.  Apparently, he said that the 185's were equipped with a 2x faster starter motor.  Anyone done this? 

Id stay far away from an Iskra, we used to use em in the construction line and had boo coo problems with em.  A 185 should have the Lucas  starter which is shorter than the ole stanby Delco starter.  The Lucases had weak fields and wouldnt take near as much as a Delco.  I dont think the Delco will fit the 433, Im thinking they came with the Lucas.  I dont know about the speeds, I was under the impression they were the same.  Sounds like yours might be getting weak.  HTH

Check the bearings in your starter. New ones are not hard to put in and often make quite a difference. If the old ones can't be driven threw run a tap in the old one. Screw a bolt in and pull the bolt and bearing out.

It matters a lot who built or rebuilt your starter.  The guy I used to work for has about 13 855 Cummins irrigation engines, so we'd go through 40MT starters quite often.  The local NAPA carries Wilson rebuilds, and the Federated Parts place carried Anderson rebuilds.  The Anderson starters could be cranked with just the 00 jumper cables, but the Wilson would use a 1000cca battery plus the jumpers, and would never crank over as fast as the Anderson.  Good cables with marine posts will help too.