fresh 355 .0023 clearences on mains and rods what oil should i be running in 60-100 degree temps. When should i switch to synthitic i have about 1000 miles on it still smokes a little under full throttle just a little but ring gaps are at .023 is that normal for 10 psi of boost and forged pistons to use a little oil or are rings not all the way seated 9.3 compression 165 psi in cylinders with a cam 224/236-114 hellfire rings also

 

what did your engine builder suggest?

 

Those are TIGHT clearances. Run a THIN oil, for sure.

Rich