New to me cm871

[Scoot5869]

Hello new to the site and first time posting.
Bought the truck with 730k on it
Changed oil had a sample done on came back a little high on iron and withtrace amounts of coolant. I have not ran an overhead yet due to lack of time and shop space. However I plan on doing that when I fix some front cover gaskets and replace the damper.

I plan on doing a short service interval 5k or so to check oil/coolant consumption before I pull trigger on inframe. Truck runs fine as far as I can tell (used to cat engines) no smoke of any kind exctfor a little right at start up.
Now that there’s a little background info my question is how do I tell if I have a bad demandate
The guy I bought it from had it done from a shop who supposedly does good work. I don’t have insite but may get it if it’s required. I plan on keeping this truck for sometime so I want to keep it in good shape. I believe it was “fixed” at 610k
Also any info or recommendations on the inframe would be appreciated I plan on using all Cummins parts new head and injectors and have a solid mechanic to do it.
Sorry for long post and thanks In advance. This is a great site!