3 1/2" Bore Super Stock Pistons / '84-'99 Evo Big Twin

A 3-1/2 inch bore 10:1 piston kit for the Evo Big Twin, supplied complete with rings, pins and clips.

Compression is the cheapest horsepower on an Evo, and a 10:1 piston is where most builds start. S&S supplies these as a complete kit rather than bare pistons, so the rings, pins and clips that have to match are already matched. Four sizes are offered, standard through plus .020 inch, so the kit suits a fresh build or a rebore.

Features of the Super Stock Piston Kit

• 3-1/2 inch bore, 10:1 compression ratio
• Kit includes pistons, rings, piston pins and clips
• Deck height is 1.3750 inch for an 80 inch engine
• Offered in standard, plus .005 inch, plus .010 inch and plus .020 inch
• Made in the U.S.A.

Fitment

• 1984-1999 Harley-Davidson Evolution Big Twin, including FXR and Dyna models
• S&S Super Stock heads are required. This piston is designed around them and is not a drop in against stock heads
• Choose your bore size above. Measure the cylinder before ordering an oversize

Before You Order

Check your cylinder measurement and head combination before ordering. An oversize piston is not returnable once the barrels have been cut to suit it.

Common Questions About the Super Stock Pistons

Do I really need the S&S heads?
Yes. S&S specifies Super Stock heads with this piston. Running them against stock heads changes the chamber relationship the piston was designed for.

Which oversize should I order?
That depends on the condition of your cylinders and what your machinist recommends after measuring. Order standard for a fresh build.

Works With

These are designed to run with S&S Super Stock Heads for the '84-'99 Evo Big Twin, which are required rather than optional.