You just got a 350 HO deluxe crate motor how long to brake it in?

if it's a zz3 or zz4, the red line is 5800 rpms, keep it under that for 500 mi. and you should be fine. I like changing the oil for the first time at 1000,mi. but it isn't a must. if it's either of the engines I mentioned, good luck . The are great engines, I've had serveral of them ,and they perform great. I found running a 600 cfm carb. with vaccuum secondaries works Excellant with those engines, and a nice set of headers help move them right along. (careful for speeding tickets)