Yea compression test is a good idea.
I just put 225/100 injectors in my 6.0 that has 350,000. Put a thumper hpop amd barder turbo. I also have the headstuds and tranny. And other little things.
My 7.3 has a 38r and tranny and tunes. It's had them since 170,000 I'm now on 220,000
My engine...