I will be picking up my new boat this friday and my friends dad said i need to break in the motor staying under 4000rpms for the first 20 hours. its a 496HO. is this true?

Don't run it at a constant RPM no matter how low. I like to play with mine on the Dyno before I run them, but I've never been afraid to run my motors up in R's after a little bit of tuning and running. I don't hold it to the wood, but I spike it up here and there. IMO 20 hours is excessive.

You can do anything you want to a stock 496HO and it will make no difference. Have fun, change the oil after 20hrs. Vary the rpms.

I am a firm believer in running the motor from day one the same way you plan on using the boat. If you baby it for a while and then change to running it hard, it will have a negative affect.

What you do need to do is change oil and filter after about 3 hours time and then at around 15 hours, then get on track for regular oil changes every 25-50 hours depending on how hard you run it.

Smitty

Run it how your going yo run it,,full throttle burst's never hurt,and as mentioned change your oil 3-5 hours..

if a engine was built right,you can run the snot out of it after 15 minutes warm up time.always let the oil warm up,then ENJOY.

I TAKE IT EASY THE FIRST FEW HOURS LET ALL THE ENGINE PARTS WEAR IN RIGTH THEN CHANGE THE OIL TO GET ALL THE PARTICLES OUT OF THE OIL FROM BREAKING IN THE EGINE . ONCE THE MOTOR HAS SOME HOURS ON IT AND THE OIL BEEN CHANGE .THEN I WILL GET ON IT AND RUN IT LIKE I WANT TO. AND ALWAYS MAKE SHORE THE MOTOR IS WARM UP BEFORE I RUN THE MOTOR HARD

Cool This has given me some good info. thanks guys

I forgot the most important thing with any motor. Make sure the engine is at normal operating temps before you hit it hard. When an engine is cold and you hit it, you severely shorten its lifespan.

FWIW, this is what I was told on my 496 (and my 2 5.0's). If your drive is new you're also breaking that in. It pretty much goes along with what everyone else is saying:

For the first 10 hours, vary the power/rpm's, no WOT runs and keep it at 4k rpm or below. At the end of that first 10 hours, change the oil/filter and drive lube.

The second 10 hours, start "sneaking up" on WOT. It's important to run it SOME at WOT, but not for long; no more than a minute at a time but the first few WOT runs should be short ones. As Smitty points out, make sure you're up to operating temps first (oil temp, not water temp).

At 20 hours, change the oil/filter and the drive lube again and you're good to go. Remember though that the "black" motors aren't purpose built racing engines and, as such, really aren't made to run wide open all the time. The longer you run them at WOT the more you shorten their life expectancy.

Our 496mag HO is at 160 hours now; runs like a champ and doesn't burn a drop of oil. It also will turn the same prop about 100rpm more than it did at the end of the break in period so I'm thinking they need a bit of run time to loosen up.