There are a lot of things going on in your change work.
The motor first;
The later heads on your early motor raised the compression ratio, hence the improved mileage and some power but watch the low octane gas from here on.
Next, the Pats theft system has to be considered if you do or don't have it beause all the newer trucks has it.
That means a flash has to be done and will it work with a 97 dash?
Next, the tunes stored in the tuner are based on a stock motor configuration.
Some of the changes move ignition timing.
At some point the increased compression may not handle the more advanced timing without ping and possibly spark knock.
You have to figure out what to do because there are too many questions that have unknown answers without trail, error and expense.
Just some background for you to hear about.
What would be nice to see now with the changes made, is a record of live data for ignition timing and fuel trims for both long term and short term table values.
If you had not noticed the newer heads have smaller and different shaped combustion chambers.
On the PCM, that's the issue.
The later PCM usually have Pats.
Unless you can get a version that did not have it trying to meet a mixed bag servicing a later dash, it's difficult unless you find a shop that can custom the program.
The PATS is normally a matter of changing a bit in a word to turn off that feature.
But trying to change readouts for tire and gear change becomes the mixed bag.
Your trying to reengineer the system, in effect.
Looking at the live data only takes a Scanner with that ability.
The mid priced units in the $200 range all should be able to do this plus you get the most important mode 6 to look at cylinder missfire counts and other data you may someday need..
Look at the Craftsman model 20890 at about $180.
It does not say to much about all this in the book but it's able to look at all this.
The info would be so huge in amount the average user would not be able to understand it for every make and model so it depends on the user to know and find it all out..