Dirty4man, you are right I totally forgot about the output shaft on the front and I shoulda remembered that since i'm about to install a 450 output shaft on my 400 since i have a spare 450 output shaft laying around. The 450 shaft sticks out about 2 inches more than the 400 shaft, meaning the 400 shaft is longer than the 450 shaft. I'll see if i can't get a picture of the shafts compared.
There have been debates on differences in the gears in a 400 and 450. Some say the 400 has lower gears (what I believe) and some say they are the same. We will find out this weekend when i tear down my 400 motor to replace the output shaft.
Also off topic but is there any difference in the 400 and 450 cam shaft?