i used atk engines about 10 or 12 years ago when i had my auto repair shop. we used the stock replacement engines not the hp. i used them for there price and warranty. i only installed 2 of them. one was a 4.3 in an astro van and one was a 2.5 in a cutlas ciera. they shipped fast and they looked really good and i didn't have any problems with either one. i was impressed with what i used and the service. they probably have a lot higher standards and tolerances with there hp line of engines.. matt