I've been watching some of these on EPay. seller only had 3. 9:1, 60-over. anyone know anything about them?
would that be ~9:1 CR, at stock deck height? (would certainly mean higher compression height) I know that chosen head, may play a part.
They are a claimed 9:1 when paired with what year block? (I know that "piston depth in the hole, while at TDC" varied, over the years) With what head?
seemed cheap enough, I went ahead and picked them up..... shipping and tax (why oh why, must EPay have to collect tax, now a days, for? nother story) wound up being slightly more, than the pistons themselves cost.
hoping I can find 3 mates, otherwise will wind up as trade bait.... apparently don't come with rings. Anybody have specs on these particular pistons? other than 60-over STD bore, how much different then stock, would these be? I know that other vendors have made MP parts before....and MP just reboxes them.

any idea on the "real" MFR of these parts? (as a potential place to source, in order to finish off the set) I never smoked, so repurpose as ashtrays wouldn't work....

If those are from the old MP catalog, then they are not 9:1. They are very close to stock compression height. Nice piston, though. Made by Sealed Power, IIRC. I put a set of those in my first fast 64 Dart engine and they worked great. If I ever get around to dropping a new crank into that motor (bad thrust bearing), then they will work again... Ran low 14s with that motor in a real street car with 10.5:1 comp and drove it 50k miles on pump premium. My first real performance buildup.

Lou

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Home of Slant6-powered fun machines since 1988

so then I wonder how they came up with "9:1" as their claimed CR? they obviously don't say anything about "when coupled with such-and such additional parts/modifications," with their claimed 9:1.
same as "any other" Sealed Power 60-over slant piston, then?
if I can't find 3 mates, for a complete set/ and it sounds like you have a set already, might you be interested in "spares"? I don't have to be in a hurry.... though I did buy on "spur of the moment". probably not the best way to buy.
what would I use for rings on these, if I can find 3 more/ as it don't appear that they come with the rings?

looking at the sticker on the box in the Ebay ad, it looks quite generic, doesn't even have the "logo" an obvious rebox from back in what ever day it was a current offering..... but the piston itself looks to be pretty beefy...

I found this in the Mopar Performance 91 Catalog.

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Hyper_pak

Huh reading that description, it makes it sound like the factory was putting out 10:1 slants back in the day? That would be a new one on me.

Especially when I hear so many stories about the advertised ratio of 8.4 but were really in the 7s, with a huge deck cut, just to get UP TO the advertised ratio? Weird.

Nope, no factory 10:1 Slants, and I can tell you those pistons will not give you 9:1 without 0.090" milled off the deck. Just sloppy/optimistic marketing. They are good pistons, but not worth hunting for. Just get a new set of Silvolites or another good brand and call it good. I have plenty of pistons for the motors I have in hand, but thanks for the offer.

Lou

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Home of Slant6-powered fun machines since 1988

They employed a simple yet powerful and versatile technique known as lying. It's not the only time, either; many of the parts in the MP cattledog were falsely described.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dang, I've been missing out on using that powerful technique for so many years...

Lou

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Home of Slant6-powered fun machines since 1988

well, I don't have them yet....have gotten shipping confirmation so far..... but 3 won't do me any good.... I either need 3 more OR someone that has some of these and wants to complete a set of their own..... the price did seem too good to be true. it apparently was.
I have an idea for a buildup, have a block, crank, and 3 heads to pick from.... 2 peanut and 1 drool tube version so far.... no pistons or rods at all, so far at present. this "engine" didn't come with them. I basically bought the pile for the super 6 stack that came with it. figured I'd try and make "lemonade" with the extras that came with the stack.


and yeah Dan, I get the concept of "lying"...

I bet you could order 3 Sealed Power 3.46" pistons and they would be very close to those MP pistons. Shop can balance them easily.

Lou

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Home of Slant6-powered fun machines since 1988

hmmm that might be the way to go... I got time to figure that out.

have the 3 that I found via EPay here.... I have not had a /6 apart in some time, last few have been 360s... these MP pistons sure seem beefy enough....
now to either find 3 more or else trade these ones off.... at this point I do not care which.

When you get them measure the compression height, the distance from the top of the piston to the top of the pin hole plus 1/2 the pin diameter. It is probably the same as a stock piston but you can raise the compression to 11:1 or more bill milling the block and head. The slant 6 head and block have enough iron to allow .090" or more on both surfaces. If they have the same compression height as a stock piston you can buy 3 more like Lou says.

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If you didn't drive it there, it's not a street car.

Yup, I know about the block and cylinder milling being a possibility and almost a necessity on these engines. Even just to get them to "advertised" compression ratio.

The 1st thing that went thru my mind about using these with 3 others of a (maybe) different brand is weight. If I can't find 3 more like these then I will probably order a set of 6 matching ones from somewhere else.