Dont ever assume your engine is built by someone unless you KNOW the person well. My 51 Cadillac motor was rebuilt but the builder forgot to clean the rocker shaft oil galleys. 2 bad shafts and 16 toasted rockers. NO OIL was able to pass the coal like sludge blocking it. Big lessoned learned. $250.00 + $100.00 core each side. Ugh!