Mopar 440 Six Pack Wrist Pin Size and Pistons: Length and Diameter

The 440 Six Pack or Six Barrel piston and wrist pin sizes are often asked. Let’s answer, what size pistons and wrist pins are in a 440 Six Pack engine?

The 440 Six Pack/6-BBL pistons are made to fit a 4.320″ engine bore size. The wrist pin is 1.0935″-1.0937″ diameter and 3.555″-3.575″ long.

Continue reading below for more of the Six pack/6BBL pistons, rings and wrist pin specifications.

Mopar 440 Six Pack/6-BBL Piston and Pin Size: Bore Size, Length and Specs

440 Six Pack Pistons & Pins
Piston Bore Size4.320″
Piston Rings3 Total
(2 compression/1 oil)
Wrist Pin TypePress fit in rod
Wrist Pin Diameter1.0935″-1.0937″
Wrist Pin Length3.555″-3.575″
Mopar 440 Six Pack or Six Barrel Piston and Wrist Pin Size

The factory compression ratio is the following for each year:

  • 1969: 10.5:1
  • 1970: 10.5:1
  • 1971: 10.3:1

The pistons are flat top with four valve reliefs. This is to provide clearance for the engine valves and avoid having the piston contact the valves.

The Speed-Pro TRW Forged 440 Six Pack replacement pistons have the following specs:

  • Part number std: L2355F
  • Flat top with 4 valve reliefs
  • Compression height/distance: 2.061″
  • Piston head volume: -7.00cc
  • Approximate compression w/.030″bore
    • w/78.5cc chambers: 10.17:1
    • w/88.0cc chambers: 9.37:1
  • Ring grooves: 5/64, 5/64, 3/16
  • Pin diameter: 1.0939″
  • Stock 6.760″ length connecting rods
  • Stock 3.750″ stroke
  • .019″ deck cir
  • .0015″skirt cir

440 Six Pack Piston Rings

The factory pistons have three rings. The top two are compression rings and the bottom is an oil ring.

The oil ring is a 3-piece design. It has two chrome plated rails with a stainless steel expander-spacer.

  • The compression ring width is .0775″-.0780″
  • The compression ring gap is .013″-.023″
  • The compression ring side clearance is .0015″-.0030″
  • The oil ring steel rails width is .025″
  • The oil ring steel rails gap is .015″-.055″
  • The oil ring steel rails side clearance is .0000″-.005″

440 Six Pack Wrist Pins

  • Wrist Pin type: Press fit in rod
  • Diameter: 1.0935″-1.0937″
  • Length: 3.555″-3.575″
  • Clearance in piston ( light thumb push @ 70°F): .00045″-.00075″
  • Interference in rod: .0007″-.0012″

Other Mopar Engine Piston and Wrist Pin Articles:

If you have any questions about the 440 Six Pack pistons or wrist pins, send us an email found specifically on our contact page.

For the past 40 years, I’ve been studying and researching Mopar engines including Six Pack pistons. I installed my first Six Barrel pistons and rings 38 years ago while building my first 440 Mopar engine.

More Mopar Engine Articles

440 Six Pack or 6-BBL Specs

440 Six Pack Main Bearing Clearances: Journal and Bore Sizes

440 Six Pack Deck Height (Plus How to Measure)

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