Best pistons

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Jun 3, 2010 | 09:10 PM

Machman

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From: Wildwood

Best pistons

Hey guys,
I am about to do a rebuild on a tired 95 EFI and need to know what the best replacement piston would be. I pretty much have the rest of it nailed down. I am trying to find out what stock piston will yield the highest reasonable compression ratio. I have looked at a few manufacturers sites and figured I would also ask everyone here to see if there was a certain favorite. So far I am leaning towards a Sealed power H519P from summit. It might not be that critical seeing that the block and head are both going to have .020 removed to clean things up. Input from anyone with experience would be greatly appreciated. Thanks.

Jun 4, 2010 | 12:49 AM

F-250 restorer

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From: Near Los Angeles

That is a good piston, the one I have. It is rated at 8.7:1, and with the .040 off it will bump your compression a little higher. I believe there is the same piston, only with the special coating on the skirts. I believe it is called 'durasheild' IIRC.

Jun 4, 2010 | 07:18 PM

Harte3

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From: Spokane, WA

Define "highest reasonable compression ratio". Reasonable for what? Low $$ gas, mid $$ gas, high $$ gas?

Jun 5, 2010 | 09:10 PM

Machman

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From: Wildwood

Thanks F-250, Glad to hear someone else has some experience with this piston. I would have thought more members would know what piston is in their rebuild. Seems like a good place to make improvements if you are that deep into it. I think it should get my compression where I want it while not creating any major problems.

Jun 5, 2010 | 11:38 PM

F-250 restorer

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Take a look at the Keith Black pistons on Summit too. IIRC they smaller recess pistons, and I believe one with a flat top. But don't guess. Go to one of the sites that help you calculate the cr, and know for certain.

Jun 6, 2010 | 09:48 AM

Machman

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From: Wildwood

The recess volume is the question. I know a stock flattop exists, but the compression height is not the same and actually yields a 7:1 compression for a different application. I guess what i am trying to find out is what stock piston with a 1.767 compression height has the lowest dish volume. A true flattop creates an unstreetable C.R.

Jun 6, 2010 | 12:22 PM

F-250 restorer

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I believe the Keith Black 3118H is what you are looking for. CR is something that can be changed by decking the block/and/or milling the head. Installing the head from a 240 is also a popular means to boost cr by a half point. I used the Fed. Mog. zh519p30, and decked block and shaved head to get where I wanted to be. If you are willing to go the extra mile with machine work, many guys use the 352 pistons, 350 chevy, or, by boring the cylinders .050 over, they install 390 pistons. Note: a nice set of sb forged pistons can be had for about $200. Making them very appealing.