Stop in for a cup of coffee
It’s like anything else, the right combo, they can easily make 1500 hp. 1500 out of a 6B is easy. We did it all the time when I worked for TST. Hell the stock rods and pistons can even handle it if you watch your cylinder temps. For about 6k in parts, you can break 1500 easy. The fuel injection pump just needs the afc screw set right and the fuel plate turned upside down or removed entirely, add 10 degrees of clocking for timing and off ya go
now getting to 2000-2500 is a bit harder, but easy compared to a gas v8.