While rebuilding the starter on my 4.108 I came across this info from a variety of sources and I thought it might save somebody some time if I put it in one place. The 20mt starter is a far superior starter to the 28mt osgr starter that precedes it.The cranking speed is much faster and in cold weather
starts much easier , definately worth the effort to track down the parts
it yourself. I will include some places with the best prices I've found to get replacement parts
Info: Delco 20MT 1107587 5E 21
, , Direct Drive, 4 terminal cap,DD series,3spline 12 tooth CW rotation HD Roller drive
Roller Drive. 1940134
Field Coil. 1960853
Brush Holder. 1988414
Soleniod Cap. Snc1161c
Drive Housing. 1968769
Drive end Bushing .627 O.D. .505 I.D.
USA Auto Elec. Repair Kit. Product I'd RK12011
and holders,Felt Brake washer,brush springs Bushings,screws etc...
Fleet Starter and Alternator
New Alternators and Starters from Fleet Alternator Starter