P5007414 Pistons

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69valiant21

69valiant21

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A good buddy has brand new set of P5007414 pistons that I could probably get pretty cheap. Not having a ton of luck finding info on them. They look like 12:1, 4.060 bore for a 4.000 crank.

Can they be used on stock crank/rods? Just won't make 12:1?
 
Those pistons have the pin located for a 3.79 stroke crank. The stock 3.58 stroke is .210" shorter. You might end up with 8:1 if you're lucky.
 
The approximate Compression heights for pistons are as follows

4.00” stroke. 1.47”
3.58” stroke. 1.67”. 360 engine
3.31” stroke. 1.80”. 340/318/273

If you run a piston with a compression height on the stock stoke engines and use a stock length connecting rod your pistons will be too far down in the cylinder for reasonable compression. You would have to make up the difference in the connecting rod and there are not any standard rod journal connecting rods I know of that will work. You are looking at custom rods most likely.

If you are staying stock stroke it is simpler in my opinion to get the right pistons and sell the ones designed for the 4.0” stroke crankshaft.

RRR treed me.
 
Rocket said:
The approximate Compression heights for pistons are as follows

4.00” stroke. 1.47”
3.58” stroke. 1.67”. 360 engine
3.31” stroke. 1.80”. 340/318/273

If you run a piston with a compression height on the stock stoke engines and use a stock length connecting rod your pistons will be too far down in the cylinder for reasonable compression. You would have to make up the difference in the connecting rod and there are not any standard rod journal connecting rods I know of that will work. You are looking at custom rods most likely.

If you are staying stock stroke it is simpler in my opinion to get the right pistons and sell the ones designed for the 4.0” stroke crankshaft.

RRR treed me.
Click to expand...
My bad. But you gave a lot more detailed answer. I'm just way too lazy for all that.
 
There is one in the parts for sale section.
A forged 3.79
 
Rocket said:
The approximate Compression heights for pistons are as follows

4.00” stroke. 1.47”
3.58” stroke. 1.67”. 360 engine
3.31” stroke. 1.80”. 340/318/273

If you run a piston with a compression height on the stock stoke engines and use a stock length connecting rod your pistons will be too far down in the cylinder for reasonable compression. You would have to make up the difference in the connecting rod and there are not any standard rod journal connecting rods I know of that will work. You are looking at custom rods most likely.

If you are staying stock stroke it is simpler in my opinion to get the right pistons and sell the ones designed for the 4.0” stroke crankshaft.

RRR treed me.
Click to expand...

So a 3.79 crank will work with stock rods? What compression ratio does that give with those pistons?
 
69valiant21 said:
360 main? Not seeing it.
Click to expand...
Oh, sorry, my bad, no, 340 mains. No one makes AFAIK a forged crank for the 360 mains except the 3.58 & 4.00 strokes.
69valiant21 said:
So a 3.79 crank will work with stock rods? What compression ratio does that give with those pistons?
Click to expand...
The 3.79 crank works with stock rods.
It’s a different rod length I think he was saying.
 
Those pistons are for a 4.00” stroke to make “12:1” compression.

it doesn’t say head cc’s. So you need to see the pistons and measure them. Then see what that ends up in compression for what you got.

Using them with a 3.79 stroke will be way to far down (0.210”) in the hole. That will not give you enough compression.

there’s a reason these are cheap. Most people running 12:1 compression want better/lighter pistons.

F8D54A34-2664-4B95-ACBE-D80D2454868B.jpeg
 
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