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Does anyone make a piston for stock stroke 400 with a 6.760 rod?

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Planning a 383 Motor
This engine is generally overlooked in selecting a high-performance project. The motor has an excellent bore to stroke ratio: 1.26-1 (similar to 327” SBC, better than 340). The short stroke allows high RPM without destructive piston speed (7100 RPM = 4000 ft./min., the accepted “safe” limit for piston stress). The large bore permits big valves (2.14” intake, 1.81” exhaust).
A potential method of increasing peak power is to substitute the longer 440 6.768” (LY) rods for the original “B” 6.358” rods on the original crank. This has the following effects:
» Increases the rod ratio (“n”) from 1.884-1 to 2.005-1
» Reduces the piston compression distance to about 1.525” for a useful weight savings
» Slightly reduces piston acceleration
This should allow an advantage in peak power. For a start in piston selection, take a look at the KB224 for BBC: flat top, CD = 1.52” (just below zero deck), and .990” pin for more weight savings and moderate cost. There may also be “possibles” for the 400 (4.34” bore), but not discovered yet. Ideas?

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You can use a 4.15 crank,6.57 rods with a 1.30 cr-height pistons that combo works real well in a low deck.

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Does anyone make a piston for stock stroke 400 with a 6.760 rod?

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Why would you want a long rod????

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Does anyone make a piston for stock stroke 400 with a 6.760 rod?

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Why would you want a long rod????

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Why not?

Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.

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While you're 451 was quite outstanding............

I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.

There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.

Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.

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Rockchip, where are ya?
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!) the rod ratio comes out at 1.932, almost ideal.
Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.

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Rockchip, where are ya?
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!) the rod ratio comes out at 1.932, almost ideal.
Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.

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If there is that CH piston he could use the Hemi spec 6.860 rod on the 383 crank and saze the cost of grinding the crank

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Does anyone make a piston for stock stroke 400 with a 6.760 rod?

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Why would you want a long rod????

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Why not?

Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.

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While you're 451 was quite outstanding............

I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.

There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.

Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.

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Does anyone make a piston for stock stroke 400 with a 6.760 rod?

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Why would you want a long rod????

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Why not?

Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.

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While you're 451 was quite outstanding............

I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.

There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.

Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.

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I spent a fair amount of time on the dyno with that little 400 engine. Stock 383 forged crank, Hemi rods, and as much compression as we could get with the short stroke. It made pretty good power for a small engine and moved the car down the track really well. I thought it was a great combo.

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Although the power benefits are debateable, wouldn't a long rod be easier on the bottom end and pistons due less side loading and less rod angularity? Probably help stave off cap walk a little longer as well

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