• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

440 Low Compression Inverse Dome or Dish Piston?

tenguns

New Member
Local time
12:51 PM
Joined
Jul 15, 2024
Messages
4
Reaction score
0
Location
Santa Barbara, CA
I'm looking for a forged piston - 440, .030 over so 4.350 diameter with a 28cc dish and or a compression height that will get me at or below 9 to 1 compression. Most importantly, are two factors. 1 is the d shaped piston top should have the dome come within 040 of the head (closed chamber 77cc) and, that it is available with the larger piston pins 1094 and not the 990s.

I'm scraping the internet to no avail. Forged, 4.350, low compression height with top being within .039 from Deck. End result - 8.5 to 9.1 compression idealy.

TIA.
 
Welcome to FBBO, maybe use the Welcome Wagon to introduce yourself and your car.

Can always use a thicker head gasket to dump the compression if that's all you're looking to do.
 
Thanks. Appreciate the welcome. I'm running a 440 .030. Stock deck. I found the JRE 345806 piston which looks like it would give me the 8.8 to 9ish compression I want. But I'm looking for quench so making sure piston is close to deck height. Realizing its not exact with mopar - is there a way to determine how far in the hole those pistons will sit? These are them. https://www.jepistons.com/product/s...iston-kit-4-350-in-bore-2-062-in-ch-24-00-cc/ Stock length Eagle rods with 1094s.
 
The problem with the later non-quench heads [ 906, 346, 452 ] is that although they flow quite well, the recessed section where a pop-up piston could create quench, is cast, not machined. So you would get a variation in quench gap, cyl to cyl. Many years ago, I had the pad on a set of these heads machined so that all were an equal depth to provide a uniform quench depth. This was before the proliferation of alum heads that are available now.

Also, there is less choice in pistons that retain the 1094 Chry pin. Better off buying a set of H beam rods with the 990 pin. You get a rod that is muuuuuuuuuch stronger than the factory rod & [ lighter ]: tougher steel, 7/16" bolts, no cut in the rod shank for the bolt head that weakens the factory rod, etc
 
Yes, I'm beyond that though at this point. I've gotva brand new set of Eagle 1094 rods in there now. This limits my piston selection.

I'm running 77cc closed chambered heads. And the D type dished piston coming close to the closed chamber I think will be better than putting in a flat top. A dish piston will keep my compression ratio low where I want it but if the piston top behind the D doesn't come within 040 of the deck, I probably lose the advantage of the closed chamber and increase the chance for predetonation.
 
Have you looked at icon? Race-tec?
Also, look at a piston manufacturer that offers one change to a stocking piston, and have them change the pin diameter.
 
Call a custom piston company (wiseco, diamond, je etc) and tell them what you want; they can make it.
 
Auto Transport Service
Back
Top