New engine break in.

[Lon_H]

Just bought a new GM 350. Besides priming the oil what do I do to break it in? What oil or oil additives do I need to use.

[Bamfster]

Roller or flat tappet cam?

[bull the rogue welder]

joe gibbs break-in oil or joe gibbs break-in oil

[Scott Liggett]

Comp Cams makes break in oil. I used Valvoline VR1 race oil. It has zinc. I've also used cheap oil with the GM additive with no problems.

Neither of these engines have crazy stiff springs.

[BOSSMAN]

I'm assuming this is a flat tappet motor so I'd run Brad Penn Break In Oil. You can typically get it locally, if not I'd order as case. Another reason why I like it is because it has a dye in it so if you aquire a oil leak you can shine a black light on it to trace it down. I typically put one bottle of zinc (or GM EOS) during initial break in and at least a couple of oil changes after but I still recommend a high zinc oil after the fact. Otherwise I would pull the valve covers to look things over and visually see oil getting to the rockers while priming. You may need to rotate the motor to a few different positions to get them all to oil. Comp Cams also has a decent tutorial on camshaft break in you may take a look at if you are not familiar with the process. Keep the motor happy with timing, fuel, and cooling for the 15 minutes or so at 2500-3000 RPM. Good luck!