Oh. Well the 5.7 Vortec, when it worked it had good power but <10 mpg. And it took years to get it's fuel supply adequately sorted. It was very sensitive to fuel pressure and the rail pump never kept up. In high demand situations (highway speeds in the mountains) with heat and altitude, you'd get cavitation in the fuel line and the engine would shut down. Troubleshooted the pumps, set up a Rube Goldberg switch between two different pump setup with fuel pressure gauge and switch on the dash. Finally, an in tank pump fixed the problem. Meanwhile, something else was always breaking. Several replacements of the spider injectors, cracked head, etc. I understand it is a popular platform for muscle cars and whatnot, but I had had enough with it.