I am just putting out the info that I have found in my own research. This data is from WIS at work and the epc. I believe it from what I have found with my own engines.
The 104.98 motor has a bore of 88.5mm with a rod center measurement from the bearing bores of 144.995-145.005. The 104.94/99 have a bore of 89.9mm and the 104.94/2.8l motor/ has a rod length of 148.995-149.005. THe 104.98/99 rod length is the same. 104.99- motors are 3.2l. I have a 104.992 currently that I am running. I took out my original 104.980 years ago but still have it. In the epc both the 103.983 and the 104992 rods update to the same part number 1020302620.
I have swapped rods and crank between the 104.980, 104.94-2.8l, and my 104.992 to see the difference. All parts go between except of course the pistons in the .980 motor are to small. I will get the stroke for each motor when I am at work today and the cranshaft part numbers. I had this data printed out for my own use at home.