S&S, steel breather valve. +.030" OD

48-E77 B.T. (NU)

+.030" oversize steel breather valve. Used to save worn or damaged crankcases. Okay for stock or high performance replacement. Note: JIMS has a +.030" breather hole reamer tool which is available as 978343. Note: that steel breathers require steel breather valve spacers. Plastic breathers require plastic spacers. Do not intermix steel and plastic parts. Note: S&S breather valves come with elongated breather holes to increase the duration of the vacuum, allowing more oil to be drawn from the cylinder heads. This has no disadvantage in any model year, either stock or Big Inch motor.