This is a BRAND NEW set of Cosworth forged aluminum Pistons for a small block Ford with Yates aluminum racing cylinder heads. These pistons are designed for use with Yates heads, but there is enough stock to mill the dome flat and use them in with other small block ford heads.

These pistons were leftovers from Junior Johnson’s NASCAR team that closed their doors back in 1995. These are from the days when NASCAR teams were ran the higher compression engines with smaller cylinder bores to make the required 358 CID engine displacement. These are dome pistons for a 12:1 motor. You will see that the specs are for a standard small block bore size! This means you do not need a special race block to use them. You can buy a brand new sportsman block from Ford and drop them right in and save a fortune over the cost of a racing block.

Here are the specs on this set of Pistons:
Cylinder Bore: 4.001"
Compression Height: 1.20"
Pin Size: .927"/2.810” (not included)
Piston type: Forged Aluminum - 12:1 Dome
Options: Gas Ported*

*One Piston in this set has been fire slotted and has been machined for a 3/16" oil ring. The remaining 7 pistons will need to be fire slotted to match the compression.

Possible Bore and Stroke Combos:
(using common crank stroke and rod combos)

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Block: 8.206” Deck (Stock 302)
3.20" Stroke + 5.400" Rods + .006" P/D Clearance= 321 cid
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Block: 9.200” Deck (Stock 351C & 351SVO Racing Block)
3.50" Stroke + 6.200" Rods + .030" P/D Clearance = 351 cid
4.00" Stroke + 6.000" Rods + .000" P/D Clearance = 402 cid
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Block: 9.500" Deck (Stock 351W & 351SVO Tall Racing Block)
3.90" Stroke + 6.400" Rods + .030" P/D Clearance = 391 cid
4.00" Stroke + 6.300" Rods + .000" P/D Clearance = 402 cid

Cosworth is legendary for making horsepower and winning races. They use a proprietary aluminum alloy in their pistons that has been proven to be one of the strongest aluminum alloys on the market today. These pistons are imported directly from Cosworth’s foundry in England. They are very expensive to purchase and are usually used only by the elite engine builders of the world. These are by far some of the best pistons available. These are the choice of many top engine builders when price is not of a concern, but where durability is a necessity. Many race teams have moved away from Cosworth over the years because of the longer lead times needed to import their pistons, but few would argue that a better piston is available anywhere else.