4.030 340 JE Pistons?????

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Bore-4.030"
Compression height- 1.217"
Piston pin .927 o.d. x 2.750" long
Piston weight- 418 grams each

Looking at the specs of those pistons...it probably for a R3 block with 9.20 deck height...small block chevy piston pin size also......the R3 block probably came at 3.91 or 4.00 bore
 
70aarcuda is probably right. Id use forged ones if you want quality. There is a lot of brands out there.
 
Only if you took them out of the box and measured them and they came out at 4.04 90 degrees from the pin across the piston skirts. Add in the typical .004 .005 for piston to wall clearance for final honing, for an actual bore size of 4.044 to 4.045. One hundred thousandths is a little loose on pistons for anything this side of blown nitro racing. With that short compression height, I would think that piston probably has to be run on the tight side to minimize piston rock, too.
 
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xLURKxDOGx said:
Thanks tony, everything I’ve read states that they’re 4.040 and was confused by the listing. Notice the box says 4.030 as well? I contacted them and they said “look, it’s right there on the box, what more is there”. Would they be good pistons to use at 4.040?

Jake
Click to expand...

Need to know what stroke you are using.....what compression are you looking at....kind of need to know what you are building...

Most of the brand names will give you a good piston....
 
70aarcuda said:
Bore-4.030"
Compression height- 1.217"
Piston pin .927 o.d. x 2.750" long
Piston weight- 418 grams each

Looking at the specs of those pistons...it probably for a R3 block with 9.20 deck height...small block chevy piston pin size also......the R3 block probably came at 3.91 or 4.00 bore
Click to expand...

Either that or they would work in a long stroke/long rod combo. Also could go into a stock .030 over 360 block with a long rod and 4.125 or 4.250 stroke. That 1/16-1/16-3/16 ring package is old fashioned for a race deal. 418gr piston with some light rods would be pretty snappy.
 
70aarcuda said:
Bore-4.030"
Compression height- 1.217"
Piston pin .927 o.d. x 2.750" long
Piston weight- 418 grams each

Looking at the specs of those pistons...it probably for a R3 block with 9.20 deck height...small block chevy piston pin size also......the R3 block probably came at 3.91 or 4.00 bore
Click to expand...

Could also go into a tall deck, long stroke, long rod deal. Also a .030 over stock 360 block. Think 4.125 or 4.250 stroke with a long rod. That 1/16-1/16-3/16 ring package is obsolete for a race deal, but a 418g. piston with light rods would make it pretty snappy. Looks like a nice piston for the money except for the ring package.
 
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