Thread: 383 break-in

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I am just having a stroker 383 built out of the original 350 from my '81 chevy 1/2 tonne truck. It is fully rollerized, 4 bolt main, edelbrock aluminum heads, chromoly rings, 150 shot of nitrous, etc. I just wanted to get some feedback on how long it will take to break in this motor and what is the best way to do so (should I vary the throttle position like breaking in a boat, run in at a continuous speed...etc) I have also heard that it would be the best to run non-synthetic 15W40 for oil and would like to get some opinions on that also. Thanks a lot.

Break-in is no mystery, just don't idle it slow, and alternate power-on , power-off more than you normally do. This puts more pressure on the rings to seat them, and then allows oil to be drawn up, power off. Of course, don't over-rev (or lug) the engine during this time.
Synthetic oil is no good for break-in. I prefer little or no additives, but oil without them is rare as junk food without salt!

thanks for the feedback, but for long should I be breaking in the engine, some people have said around 1500 kms some have said 4000 kms......

Chris, I would recommend Shell Rotella oil for break-in...and for later for that matter. It's used by most fleets for their diesel trucks, and has all the agents and additives that were taken out of the 'regular' oils that we usually buy now. I, and several others, have very high praise for it. 15-40 is what I use, I believe that's the only way you can buy it, but I may be wrong on that. Dont use synthetics for break-in, but they're fine for after, if that's the way you want to go. I just prefer the petroleum based oils, that's all. And you will get a lot of opinions on breaking in a new engine, but all I have ever done is drive it like you are going to drive it normally. I never babied a new engine during break-in. I have built several, and do them all the same. The only exception to this would be if you are using a flat tappet cam, you do have to break that in properly, but if you're having an engine built for you, Im assuming that will already be done. Check and find out so you know for sure. Lots of guys I know are hard core drag racers, and when they finish an engine, they just go to the track and run it....no break in period there, right? Just run it. Have fun!! John