OK, I got the new smooth shaft motor in the mail today. I ran out this evening to see if it fit. I will have to admit the waiting has been a bit nerve wracking for me being that I ran out last week and had the case milled based on the gear alone.
But, the motor fits fine with the gear, now I can complete clean up and assemble. A relief.
Here's some pics. I also included the two electric motor specs from Western motor. Just for easy reference for the next guy or gal.
Everything fit... so far
The old 10 spline and new smooth shaft
Here's the specs for both motor form Western Motor. Also, I want to point out that the raised ring diameter(3") and the shaft length(1-7/8") is same for the 10 spline... even though it's not stated on the MBJ-4301 spec.