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Discussion Starter #1
Hey guys,
Just got off the phone with Dan Newman about Pistons. Someone (Can't remember who) on this forum suggested that I should get Cobra pistons for my engine to help up the CR. I have a 95 block with PnP'd 96 Heads w/pi cams. I asked for prices and he said there are two different kinds, one for a 96-97 for 52 bucks a piece, or 98 + for 28 a piece. Can someone tell me which ones I am supposed to buy? I am hoping obviously that it ill be the 98+ ones. There is a big difference in price so now I am leery about the possibility of buying the wrong one for my engine. Help??

Thanks,
Pappy
 

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Sheepish
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I know the 99+ Cobra pistons are flat top which will give you a nice compression raise, not sure about the older cobra pistons though...
 

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Discussion Starter #3
Thanks for the info!! Does anyone on this board use Cobra pistons? If used how much would it raise CR?
 

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99+ Cobra pistons flattop???? I'd have to disagree with you on that one, since I've been working on a '99 Cobra motor for the last 3 weeks, the pistons are definately NOT flattops, they have a slight dish to them.
 

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Discussion Starter #5
I think the Cobra pistons are 3cc dished as opposed to our regular 9.5 cc dished. This is only what I heard, but I don't know for sure. Does anyone sell actual FLAT top pistons? Will flat tops even work on our motors??
 

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Sheepish
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www.modularperformance.com sells all the pistons you need.

Rich, they may have an ever so slight dish to them, but when I looked at the pistons Joe Lynch pulled out of his Cobra, they were so close to being flattops its not even funny.
 

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Well, I guess I'm just too much from the old school, because when someone says flattops, I think of true flattops, with no dish what so ever. The Cobra pistons have a definate dish, that starts about a 1/2 inch from the edge. modmax has flattops for sale, and I've seen them, they are true flattops. The Cobra pistons do have a small dish, but it's still a dish, and if anyone wants one, I have a set of 8. 4 are good, but 4 are missing ring lands:D That's what happens when you're running 9lbs of boost and hit the factory rev limiter and it cuts fuel. (idiot was racing another Mustang and got overexcited)
 

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Refrigerator Raider Hater
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Whoa people! Did anyone stop and contemplate the CR he will get with cobra (3cc dish) pistons and PI heads? A quick calc says it'll be 11.4 to 1. Thats not very streetable, as even 93 octane would require some timing retard.
 

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Discussion Starter #10
According to Modmax, I should get around 10.30:1 and that is with true flat tops, not the cobra 3cc dish. Is this not a good thing???

Also, around what cr does a car become "not streetable"?
 

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Sheepish
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Well a CR of around 10-10.5:1 is plenty streetable. Thats the ratio you wind up with when you throw PI heads on an NPI shortblock.
 

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High-Mileage 4.6L Thrasher
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Here's your difference in the pistons...
the earlier pistons use a 1.5/1.5/3.0mm ring package.the '98-up use a 1.2/1.5/3.0mm ring package..price the ringset for both and see which one comes out less expensive.The plus to the shorter ring package is less friction....but also less life from less material to begin with.You'll end up with 10.3-10.5:1 CR...kinda evens things up compared to the PI swap guys.
JL
 

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I remember talking to DAn quite some time ago about the same topic. The earlier pistons would be the ones to get. I believe Dan said they are stronger than the newer ones. But don't quote me on that on, it's been far too long since I've investigated this. :cool:
 
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