I recently purchased a ZZ502 Deluxe crate engine from summitracing, brand new with 24 month/50,000 mile warranty from GM Performance Parts. Had it installed at a professional shop that is local to me (won't put them on blast yet, gonna give them a chance to make this right). I'm assuming since they have installed over 20 of them before and have been open for 30 years that they followed proper break-in procedure. After 300 miles my carburetor went bad (was the factory Holley 870), replaced it and the engine ran fine. At 500 miles had break-in oil changed and regular oil put in at shop that installed the engine. The engine lasted 300 miles after break in and developed a rattling noise between 2,000-2,500 RPM, I brought it to him, the next day he calls me and he pulled the engine and was already pulling apart the bottom end to see what was wrong. He determined that the bearings failed due to lack of lubrication, consequently ruining a brand new forged steel crank and brand new bearings. Now he is saying GM won't cover this failure and I now have to pay 4-500$ for machine work and foot the bill for labor of reassembly and installation. Just putting my experience out there, if you were thinking about getting a crate engine I would highly reconsider. These warranties aren't what they seem, and these 500 horsepower crate engines aren't what they seem, my mechanic is blaming me for driving it too hard (only reason i bought the engine was he said it was reliable power with a warranty). I never even got to replace the tires so clearly I didn't drive it all that hard because that engine was more than capable of destroying a set of 275s.