I really have no idea on the seat materials other than most airplane motors are air cooled and run under 2700 RPM
The sleeves are steel and the block and heads are aluminum
I had one exhaust valve spit a pie shape chunk out of my airplane motor at 8500 ft at 190 MPH about 50 miles east of Needles, CA, that made me turn around and go back to the Prescott, AZ airport real quickly. I had been running that mixtured at +25F rich of peak on the single probe EGT up to then, I ran it +75 F after that