450 question???

[JD-thomas]

I have a 450AA french model it had a M53 motor in it.. I am looking to replace it with a 4039 out of an air compressor it is a "99 model motor with 900 hours on it complete with flywheel, inj. pump, and starter he wants a 1000.00 for it. Any input would be appreciated. How much power difference if any will there be?? I never ran this machine with the M53 so I dont know it. I have a 450 with a 4202 in it, and I am happy with it. Thanks for any help!