need help with engines

I have a 450 cylinder on my 400 and yes a 400 bottom end will bolt in where a 450 does. They are the same engines just the cylinder bore is different.

I am not for sure about the the 95 model foreman 400 motor, but the output shalfs on a 98 foreman 400 motor are shorter than the 450 foreman output shalfs. you might have problems with the drive shalfs. I have a 450 motor in a 400 frame and had to change over to 450 driveshalfs for it to hook up. everything else will hook up fine as ctown said.

They are the same crankcases ... The final shaft is different and some gears are different between the TRX400 & TRX450 ..

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?

HM thanks for the #'s

Well there is something in them there 400 motors that are lower, I swears by it.

Just wondering if it would be worth it to install a 450 cam shaft i have laying around in the 400 if it would make a difference.