a 40 is numbered on my piston

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bowtietrader

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#1

• Aug 18, 2004

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i just bought this 88 GT and im doing a bunch of mods to it..when i pulled my heads off, each piston has a 40 stamped on the top..is this a a stock piston??
thanks

 

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87'GTstang

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Feb 16, 2004

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#2

• Aug 18, 2004

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Could mean a .040 overbore piston, or less likely - the weight in some measurement.

 

dastang2

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tx

Aug 18, 2004

#3

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your engine has been rebored to .040. they may or may not be stock replacements

 

BlackFox5.0

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Aug 18, 2004

#4

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I've never seen them stamped with just a number, usually it's .030 or the like, but it's possible they are .040 over pistons. Mine say .030 on them when i put them in, of course it was bored .030.

 

8

87'GTstang

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BlackFox5.0 said:

I've never seen them stamped with just a number, usually it's .030 or the like, but it's possible they are .040 over pistons. Mine say .030 on them when i put them in, of course it was bored .030.

Click to expand...

Yeah the number is usually a little more accurate then just a number put on it. Then again though, what kind of quality the pistons are should dictate that.

 

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bowtietrader

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ok so the piston is probably stock, but it is bored more than likely..??
thanks again

 

dastang2

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tx

Aug 18, 2004

#7

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• #7

if you can get a mic and check the cylinders then we can tell if it was bored. or get a ruler and measure the middle of the bore. if it is .40 over then it will be a little over 4 inches across.i have .60 pistons and they have 0.60 on them. once you get to 0.40, it gets harder to cool the engine. but i don't have that problem.

 

Dan95-5.0

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Aug 18, 2004

#8

• Aug 18, 2004

• #8

the motor has been bored .040 over. is there any other numbers anywhere on the piston? in order to fit this .040 over piston into the block it has to be bored .040. what does the piston look like? dish, dome, valve releifs? it could be a stock replacement piston but just .040 oversize.

 

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bowtietrader

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#9

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the size is over 4 inches..

 

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bowtietrader

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whats a few emails, ill send you the pic...the email thing is turned off

 

cardudeusa

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Email it to cardudeusa@hotmail.com and I will host it so everyone can see it from here.

 

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bowtietrader

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sent

 

cardudeusa

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#13

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Heres the picture, hosting this for bowtietrader, it doesn't look stock, almost looks like it has a bit of a dish to it.

 

cardudeusa

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Thats wierd, the picture shows up on cardomain, but a red x here. Go figure.

 

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bowtietrader

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ok well let me know if you have any idea....????

 

cardudeusa

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#16

• Aug 19, 2004

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Here, let me try again.

 

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tjm73

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Aug 19, 2004

#17

• Aug 19, 2004

• #17

You have a rebuilt block with 4.040" total bore. So you have a .040" over bore 302. They are not stock pistons. They are replacement stock type, but bigger. That's about as big as you can overbore a 302. You can do .060" on some blocks , but as a rule of thumb, .040" is max overbore.

If it needs to be bored, you will need a different block.

 

dastang2

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tx

Aug 19, 2004

#18

• Aug 19, 2004

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i got 0.60 and it is a block from a 90 truck. you can bore that far only if the block is not too screwed up that it has to be bored more than that extra 0.20.

 

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bowtietrader

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so what would make that in cubic inches??
thanks again

 

MustangPunk302

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#20

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Like a 308 or so...