425 toro heads off
August 10th, 2013, 08:33 AM
#1
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Location: fort wayne, indiana
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425 toro heads off
I pulled the heads pistons look fine one has a DD stamped or engraved I don't know what it means if anything...any ideas? Will post pic when I can I'm on my phone .
Last edited by lowkey235; August 10th, 2013 at 08:51 AM.
August 10th, 2013, 09:27 AM
#2
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I hope there is a D stamped into the deck surface next to that bore.
That means they fell asleep at the hone machine and honed that bore out to the largest still-std size, coded "D" and so they put a D [or DD in this case] piston in it to match. Can you find all the cylinders' size code letters?
That means they fell asleep at the hone machine and honed that bore out to the largest still-std size, coded "D" and so they put a D [or DD in this case] piston in it to match. Can you find all the cylinders' size code letters?
Last edited by Octania; August 10th, 2013 at 10:38 AM.
August 10th, 2013, 10:06 AM
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There is an x on the cylinder head under the rockers in that position.I'm unsure of cylinder size code letters...I couldn't find them in my shop manual
Last edited by lowkey235; August 10th, 2013 at 10:10 AM.
August 10th, 2013, 10:48 AM
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Here's some typical stamps:
10037_68-G400_32aCcodeBORESW30maybe_zps1f28469d.jpg
7099_ENGINE-350-8_CN23CBorestamp_zpsd0710588.jpg
7009_Pad_ENGINE_CN64BorestampB_zpsfd1f4c2d.jpg
9325_65-330_CN31BoresCC_zpsd2d1af73.jpg
3189_Rblt-350_Bore-Size-StampB_zps99282f90.jpg
It's a factory exact size tolerance stamp. Means little at this point.
10037_68-G400_32aCcodeBORESW30maybe_zps1f28469d.jpg
7099_ENGINE-350-8_CN23CBorestamp_zpsd0710588.jpg
7009_Pad_ENGINE_CN64BorestampB_zpsfd1f4c2d.jpg
9325_65-330_CN31BoresCC_zpsd2d1af73.jpg
3189_Rblt-350_Bore-Size-StampB_zps99282f90.jpg
It's a factory exact size tolerance stamp. Means little at this point.
Last edited by Octania; August 10th, 2013 at 10:51 AM.
August 11th, 2013, 02:29 PM
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I found a chart for an early 70s 455 with block and piston codes..c block and d piston keep me with standard rings, if I am correct that the stroke is the difference between 425 and 455 blocks
August 11th, 2013, 03:01 PM
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Correct.
A, B, C, D are all subtle variations (like a few TEN-Thousandths of an inch) on the std bore size, like [but these figures are picked out of the air, not the manual]:
A = 4.1250-4.1254
B = 4.1255-4.1259
etc.
ABOVE FIGURES ARE GUESSES, not real factory numbers! From my feeble memory.... Check the Chassis Service Manuals for real exact numbers. Perhaps part number manuals.
Yes, the stroke [Crank, rods, pistons] is the difference between the 425 and the 455.
A, B, C, D are all subtle variations (like a few TEN-Thousandths of an inch) on the std bore size, like [but these figures are picked out of the air, not the manual]:
A = 4.1250-4.1254
B = 4.1255-4.1259
etc.
ABOVE FIGURES ARE GUESSES, not real factory numbers! From my feeble memory.... Check the Chassis Service Manuals for real exact numbers. Perhaps part number manuals.
Yes, the stroke [Crank, rods, pistons] is the difference between the 425 and the 455.
August 12th, 2013, 06:11 AM
#11
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Remember, you can put the entire rotating assembly from either in either block. IE, put the assembly from a 455 in a 425 block or the assembly from a 425 in a 455 block. The cubic inches match the rotating assembly.
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