i just finished building a 355 LT1.. i've was told to break the engine in with 20w50 for the first 500, change @500 with 20w50 again, then after 1000miles, 10w30 or 40.. then at 2000, i can run synthetics... i've also heard to use SAE30 for the 2 break in periods... what did everyone use to break in their new motors?

thanks
vinnie

 

I used 40 straight weight, non-synthetic until 1500 miles.

Mike

 

anymore opinions??

thanks

 

I just finished my motor and am running 10w30 for the first 500miles, then probably 10w30 again.