As Contender posted. Hammer heights vary slightly but here are the four basic size ranges.
1. OM hammer heights measured from bottom surface to top front:
Large frame hammer = 2.370" - 2.380"
Mid-frame = 2.180" - 2.220"
Single six, tall for fixed sight = 2.035" to 2.060"
Super single six, shorter for adj. sight = 1.945" to 1.965"
2. 3 sizes of cyl pin lengths for 3 frame sizes, but the conversion pin can be used with the old parts
3. cyl hands, two sizes, small frame and mid/large frame. The conversion hand can be used with old parts, it's the same part.
4. The cyl bolt (latch) is the same for all frame sizes
5. The conversion trigger cab be used with old parts, it just needs the transfer bar mounting lever hack sawed off the trigger.
Hope this helps,