Is the K341 the original engine to the tractor?
If it is the original engine I would do a stock rebuild. IH Cub Cadet 169's are the 2nd lowest production Cub Cadet made. Only a little over 4000 units were made.
If it was my tractor and I had the hot rod inkling I would find another K341.
I would keep RPM's below 4000 rpm the cast iron flywheel and crank were not design to run over 4000 rpm. Nasty things can happen when they fly apart over 4000 rpm.
Here is a site that can help you out:
http://www.kirkengines.com/