I have a brand new 350 roller cam engine installed now. I've got break in oil in it at the moment. I've heard conflicting reports in so far as of when change it. I have been told to change it at 3000 miles and then someone else said changes at 50 miles then 150 miles and then 1500 miles. So which one should I do?

 

Did you buy a new GM crate engine? Go by whatever the manual says, I'm pretty sure for my Fastburn 385 the mileage was 500 miles for break-in.

 

It's an ATK reman if that helps.

 

Drive it like you stole it. Its a roller cam so dont overthink it. I never treated a new engine any different than I normally treat one broken in. Never had an issue in the 34 years I have been driving.

 

^agreed for sure^ All you're doing during the break in is running thicker oil, and making sure to get some full throttle pulls in somewhere in the mix. Don't go easy on it, that's for sure.

 

I wanted to provide a better answer for the next person who searches this topic.

"Drive it like you stole it" sounds great for a random message board, internet screen name response...who won't be providing you with a warranty. Since I am going to be buying an ATK reman engine coming up, I had already checked their break-in procedure.

This means that you, as the owner, need to follow their break-in procedure and guidelines. Here is a snippet:

BREAK-IN PROCEDURES - ENGINES
Your ATK remanufactured engine requires special care during its initial “break-in”
period. To ensure your engines long life expectancy and proper engine performance,
please follow these procedures during the first 600 miles of operation.
Do not drive for long periods at any single speed, always vary your speed.
Do not tow a trailer or put other heavy loads on the vehicle.
Check the engine oil and coolant levels daily.

600 MILE CHECKUP - ENGINES
Check fuel and ignition settings.
Change engine oil and filter.
Adjust Valves (where applicable).
ATK does not recommend using synthetic engine oil until after the first 5,000 of
service. Follow your vehicle owner’s manual for service intervals.

The common sense summary is to vary the speed and engine RPM (without beating on it) and treat it right. No synthetic oil for 1st 5,000 miles. And be prepared to document this, if possible (receipts, etc). Why? Because you may do everything right and still have the engine fail. During their teardown of the engine, THEY (ATK) determine if you treated the engine right and what caused the failure...not me or the internet.

I am getting more cynical as I get older, but I have too much life experience seeing various warranty companies try like HELL to deny warranty coverage. If you don't care about the warranty, then do whatever you would like