20-ish years ago we had a motor(BBC) come to the shop that had a main bearing problem.
It had been run in the car(S/G Roadster) for about a season and a half.
It was built by one of the big name engine builders that used to have big multi-page ads in the National Dragster.
The car never went as fast as it was supposed to go, based on the numbers on the dyno sheet.
And thousands of dollars had been spent on “upgrades” to get the car quicker. None made any real difference.
The dyno sheet showed 812hp.

After the motor was torn down, and things evaluated...... it didn’t really seem like a combo of parts that would make 812hp.
I looked at the cam specs, and flowed the heads........ and it really looked like a pile of parts that would make about 725hp.

Block got line honed, crank ground, valve job refreshed...... new rings/bearings/gaskets..... and back on the dyno.
Made right about 725hp with the timing/jetting/lash set the way he had been running it.
We messed with those adjustments a bit...... found less than 10hp. Iiwii.
So, it goes back in the car with supposedly about 85hp less than it made before.
Ran .03 quicker.
That car was running as good as 730hp was going to push it.

A couple seasons later we made some big changes to it(heads & cam)....... and then it was making a bit over 800hp....... and then it ran like it had 800hp.