i will check the length in the morning, i dont recall from my mod, a lot of guys run the pre 09 450 shock on wider arms with no adapter plates, however your shock angle will be different from what it should be and so it compression and geometry will be out!
If I were you, id try keep the shock angle the same as stock, this would involve a plate as you mentioned, however this will probably jack up your ride height...so a compromise between the two must be found
measure the ride height off the ground with a tape measure with the wheels on (stock) then put a jack under the fram with the wheels off and use a tape measure to adjust the height to the same and fit the new shocks to the a arms and see where the bolt holes need to be, then if its extreme, raise the frame till the top shock mounts are in an acceptable position
I explained more about how i did this in my sticky in the suspension section where i showed how i did my 450 setup.
If I were you, id try keep the shock angle the same as stock, this would involve a plate as you mentioned, however this will probably jack up your ride height...so a compromise between the two must be found
measure the ride height off the ground with a tape measure with the wheels on (stock) then put a jack under the fram with the wheels off and use a tape measure to adjust the height to the same and fit the new shocks to the a arms and see where the bolt holes need to be, then if its extreme, raise the frame till the top shock mounts are in an acceptable position
I explained more about how i did this in my sticky in the suspension section where i showed how i did my 450 setup.
