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Where to get new pistons 1981 318

Re: Where to get new pistons

Suggestion:

Keep in mind that the 318/360 Chrysler cylinder head incorporates a "wedge" area, very similar to some of the larger Chrysler engines, and the SBC.
IOW, the shape of the combustion chamber is not hemisperical.

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I'm not enough of a Chrysler Marine buff to know which pistons were OEM in the Marine version.
But if this includes the full dished piston.... this would NOT be a good choice, IMO.

For example... this full dished piston is listed as a Chrysler 360 piston.
This piston offers no quench or squish area when used with this style cylinder head.
FED405P.jpg


One of the huge problems for the Gasoline Marine engine is Detonation Potential.
The above piston does nothing to help control detonation..... in fact, it can lead to increased Detonation potential.
It also causes us to hold back some on Ignition TA (leaving some performance on the table).

Read up on what you can about the correct style piston that would offer a Quench Effect or Squish Effect!
The 440 Wedge Head Chrysler boys know about Quench Effect.

Do a search, I'm sure that you will find information regarding this.
If the Q/E can be applied to the 318/360, it would sure be worth checking into.

Something more along the lines of this style piston may offer you the Quench (aka Squish), yet allow for the correct C/R.
Any good piston supplier can recommend and supply the correct piston for this.
BTW, these may be known as; Low Compression Quench, Quench Effect, or Reverse Dome pistons.

Example only: (although this is listed as a 360 Reverse Dome piston)
images

Note the portion of the piston that will "mirror" the wedge area of the cylinder head.
This creates the "Quench" or "Squish" as the piston nears the cylinder head.
This makes for a much better burn!
Nothing regarding C/R needs to change when the correct piston is selected.
The volume of the dished area brings C/R back into spec, or whatever you want it to be!
Now your choice becomes which material you want these in...... i.e., Hypereutectic, cast aluminum, forged aluminum, etc. $$$$$ or $$

While the goal is not entirely a horse power increase, detonation control is enhanced greatly.
A few more degrees of TA can now be thrown at the engine.

Food for thought!
 
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