I'm getting ready to fire up my newly rebuilt SBC 357(?)
(350 .040 over). It has Speed Pro file-to-fit rings(R-9342). What grade non-synthetic oil should I use for the initial break-in?
0w-30 or 10w-30
I use straight 30wt and I would suggest a can of GM EOS (engine oil suppliment). I am assuming this is a flat tappet cam? If so you might want to find some Valvoline Racing oil (has more zink) to help prevent a cam failure.
After initial break in change the oil and filter and run whichever oil you prefer.
Straight 30w will be sufficent and do like camaroman said and run engine oil supplement (GM EOS) also. RPM speeds above 2,300 on break in take the load off the cam during break-in. The cam you put in it should have a recommended break in RPM. Goodluck!:thumbup: