The PLUS is for the extra additives above and beyond the normal additive package found in ordinary racing oils. This true high performance lubricant was especially developed to protect top fuel engines. This was tested extensively on the 1996 NHRA circuit and every crew who used it claimed it to the BEST. 50,60 & 70 PLUS resists fuel dilution like no other oil possibly can. It allows you to maintain oil pressure from one end of the track to the other. Has extra additives over and above regular racing oils. Resists breakdown from racing fuel contamination. Resists oxidation and thinning out at high crank-case temperatures. Contains a high level of detergents and dispersants. Resist sludge and varnish formations.