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Author
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Topic: Off the shelf Pistons
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jsracingbbf
Gearhead Posts: 2805
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 06-26-2004 12:04 PM
   
I am building a new motor and I'd like to get some suggestions on pistons. new motor is a 30 over block 460 of course
6.8 rods
4.5 inch Scat crank.
I want at least 12.5.1 CR. flat tops would be close to that. Anyone know of an off the shelf Piston either flat top or mild dome for this set up? ------------------
JS
"never submit yourself to scientific tests no matter how bad you need the money, for all you know they could have erased your memory and YOU WERE REALLY SOMEBODY BEFORE"
69 Mustang Pro ET Drag
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Dave_C
Gearhead Posts: 994
From: Gadsden, Al
Registered: Aug 99
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posted 06-26-2004 05:45 PM
Jerry, I have Probe flat tops in my 557. These were made from Ross blanks. Same stroke as yours, but .080 over. With 80cc heads mine works out to 12.2 : 1 It maybe hard to find some that will be that high with that combo. Lot's out there at .080 over. You might have to go custom if you want to stay at .030 with the 6.8 rods. Probe makes a set in .030 for that stroke that would put you where you want, but they are for a 6.700 rod. Later,
David Cole ------------------
557 BBF Powered, alcohol injected rear engine dragster. 4.90 @ 143 1/8 mile. 1.09 60'. I've got to be crazy to drive this thing.
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jsracingbbf
Gearhead Posts: 2805
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 06-26-2004 06:51 PM
Dave I think I found a set for a 30 over block in a Probe Piston. How do you like your Probe Piston's I have heard a few horror stories about Probe. I run JE's in my 514 combo.
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Dave_C
Gearhead Posts: 994
From: Gadsden, Al
Registered: Aug 99
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posted 06-26-2004 08:26 PM
I like mine just fine. No problems. YMMV though. Two items to consider. 1. Older Probe pistons were made from Ross blanks. I've heard a few things about newer pistons having problems. Newer meaning since they went to their own forging instead of Ross. On mine you can still see where they once said Ross on the bottom side. They just ground the word Ross off.2. The ones I have heard bad things about were their dish top pistons. The dish is a bad design, just a simple round dish. Very prone to detonation in a street engine. Doesn't apply to us as we are both on alky and flat tops are another story. The Probe flat tops look just like the ones JE sells. Flat with a single large valve relief. Here is the page for Probe flat tops for a 545. (4.50 stroke X .030 over 460)
http://www.probeindustries.com/Pistons/Pistons_SRS/Ford/460/Ford_545_ft.htm Take note of the lower compression #'s for their pistons for a 6.8 rod. Perhaps they have another part # listed elsewhere for higher compression. I personally love having flat tops in a large alky engine. People can't believe the compression is only 12.2:1. I think the flat top and rather small chamber give very good flame travel and a good burn vs a dome piston. Later,
David Cole ------------------
557 BBF Powered, alcohol injected rear engine dragster. 4.90 @ 143 1/8 mile. 1.09 60'. I've got to be crazy to drive this thing.
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jsracingbbf
Gearhead Posts: 2805
From: Batesville,MS. , U.S.A.
Registered: Mar 2002
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posted 06-26-2004 10:04 PM
Dave I talked to Brian Adams and he said to note the -3 on both of those pistons. I can't figure out how they can go to a lower CR and have the same -3 cc valve relief. Brian Said it was a misprint on their web page. I want to stay where I am CR wise.
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