Cast iron block 3.5 swap for 3.5 HO
 

My 01 300M has a bad top end engine noise / rattle. Can't locate a reasonably priced aluminum block HO, but have been told that the cast iron block, non-interference pre 98 3.5, will bolt up, but will not run with 01 electronics. Is this correct, or is there a way to make it work?
I would like to keep my 300M going, even if it's with a little less HP.