Identifying Chevy engines

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==Overview==
 
==Overview==
 
Identifying Chevy engines isn't that difficult if all that's needed is to know whether it's a BBC or SBC, or a six or V8, etc. But to get into the finer points requires digging deeper.
 
Identifying Chevy engines isn't that difficult if all that's needed is to know whether it's a BBC or SBC, or a six or V8, etc. But to get into the finer points requires digging deeper.
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==Block casting number==
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These are generally by the transmission mounting surface of the block. The date code will usually be on the opposite side from the casting number, but not always. It is common for just the last three numbers to be referred to when dealing with casting numbers, i.e. an "880" block would be c/n 10243880. Usually the last three numbers aren't repeated but there are cases like the SBC head c/n "462" that- for some unknown reason- was reused 5 times! Fortunately this is rare.==Casting numbers==
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One of the easiest way to identify a Chevrolet engine is by the casting number (c/n) that is cast into the castings (not stamped). [[Chevy engine casting numbers]] has several sites that are useful.
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===SBC engine casting numbers===
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*[http://web.archive.org/web/20080506065350/www.mortec.com/castnum.htm Mortec SBC], archived
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*[http://www.nastyz28.com/sbchevy/sblock.html smallblock info] from nastyz28.com
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*[http://www.73-87.com/chevy_ids/sbcid2.htm SBC ID] from www.73-87.com
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*[http://www.classictruckshop.com/castgm_smblock.asp SBC casting numbers] from classictruckshop.com
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*[http://www.inliners.org/becks/BCN2.html Inline engine casting numbers] from inliners.org
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===BBC casting numbers===
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*[http://www.nastyz28.com/bbcmenu.php Big Block Chevy Engine Parts Identification] from nastyz28.com
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*[http://web.archive.org/web/20080513040220/www.mortec.com/bbc.htm Mortec BBC], archived
  
 
==Suffix codes==
 
==Suffix codes==
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*[http://chevymania.com/partsid/suffix.cfm?block=Small SBC suffix code list] from Chevymania.com
 
*[http://chevymania.com/partsid/suffix.cfm?block=Small SBC suffix code list] from Chevymania.com
 
*[http://chevymania.com/partsid/suffix.cfm?block=Big BBC suffix code list] from Chevymania.com
 
*[http://chevymania.com/partsid/suffix.cfm?block=Big BBC suffix code list] from Chevymania.com
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*[http://www.nastyz28.com/chevy-engine-code-stampings.php Suffix and VIN codes] from nastyz28.com
  
==Casting numbers==
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==Date code==
One of the easiest way to identify a Chevrolet engine is by the casting number (c/n) that is cast into the castings (not stamped). [[Chevy engine casting numbers]] has several sites that are useful.
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===Block casting number===
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These are generally by the transmission mounting surface of the block. The date code will usually be on the opposite side from the casting number, but not always. It is common for just the last three numbers to be referred to when dealing with casting numbers, i.e. an "880" block would be c/n 10243880. Usually the last three numbers aren't repeated but there are cases like the SBC head c/n "462" that- for some unknown reason- was reused 5 times! Fortunately this is rare.
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===Date code===
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The date code generally has a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year.  
 
The date code generally has a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year.  
 
Example: D123 = April 12, of a year ending in 3 (1963, '73, '83, etc.)
 
Example: D123 = April 12, of a year ending in 3 (1963, '73, '83, etc.)
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'''Note:''' There is a flat tappet block and a roller block that both end with the numbers 148. 14101148 is a flat tappet truck block, 14011148 is a roller provisioned block.  
 
'''Note:''' There is a flat tappet block and a roller block that both end with the numbers 148. 14101148 is a flat tappet truck block, 14011148 is a roller provisioned block.  
  
===SBC Head casting numbers===
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==SBC Head casting numbers==
*[http://outintheshop.com/faq/casting/castings2.html SBC head casting number "go-to" site]
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*[http://outintheshop.com/faq/casting/castings2.html SBC head casting number "go-to" site] from outintheshop.com
*[http://web.archive.org/web/20080518030656/http://www.mortec.com/ MorTec, archived]
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*[http://web.archive.org/web/20080518030656/http://www.mortec.com/ MorTec], archived
*[http://chevytech.info/3c10o12.html Head info by c/n, some with photos]
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*[http://chevytech.info/3c10o12.html Head info by c/n, some with photos] from chevytech
  
 
==Dampers/balancers==
 
==Dampers/balancers==
 
===SBC===
 
===SBC===
On a 350 SBC engine and internally balanced stroker engines, there will be no discernible difference in the dampers- they are neutral balanced.
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The earliest SBC 265 dampers had a riveted on crank pulley (red arrow) attached to a steel hub, as shown below.
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{|
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|[[File:Sbc 265 damper.jpg|thumb|left|500px|SBC 265 damper hub with attached pulley, front]]
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|[[File:Sbc 265 damper2.jpg|thumb|left|500px|SBC 265 damper hub, back]]
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|}
  
On the 400 SBC and externally balanced stroker engines, an OEM damper will have a scalloped portion to the outer ring which is easily seen. Aftermarket dampers usually use a bolted on counterweight, which is also usually easily seen.
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On other SBC engines, including internally balanced stroker engines, the dampers are neutral balanced. The differences will be in the location of the TDC line, weight, thickness and diameter of the dampers.
  
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On the 400 SBC and externally balanced stroker engines, an OEM damper will have a scalloped portion to the outer ring which is easily seen. Aftermarket dampers usually use a bolted on counterweight, which is also usually easily seen.
 
[[File:Sbc400balancer.jpg|thumb|300px|left|OEM 400 balancer. Note scalloped outer ring]] <br style="clear:both"/>
 
[[File:Sbc400balancer.jpg|thumb|300px|left|OEM 400 balancer. Note scalloped outer ring]] <br style="clear:both"/>
  
===Starter bolt hole location===
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===BBC===
Flywheels having two different diameters and tooth counts are used on Chevrolet small block V8, big block V8, and V6/90-degree engines: 
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The 396/402 and 427 ci BBC engines were internally balanced. The 454 BBC engine is externally balanced. The 454 can be ID'd by the balancer having the inner hub cast with an integral counterweight. A 454 will also have a different flexplate/flywheel, having an added counterweight that is missing from the other displacement BBC engines. Like the SBC aftermarket dampers, the counterweight of a 454 damper might be bolted to the hub.
*Large flywheels are 14" in diameter, and have 168 teeth on the starter ring gear.  
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*Small flywheels are 12-3/4" in diameter, and have 153 teeth on the starter ring gear.
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The difference in flywheel diameters requires two different starter noses. Starter noses used with the large diameter flywheel have two offset bolt holes.
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[[File:Bbc 454 damper.jpg|thumb|left|500px|BBC 454 balancer with inner ring scalloped]] <br style="clear:both"/>
  
[[Image:Staggered_Chevy_starter.JPG|thumb|350px|left|Staggered bolt pattern for the large 168 tooth SBC flywheel/flexplate]] <br style="clear:both"/>
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A BBC block may have bores notched to clear the intake valves. Not present on all BBC engines.
 
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[[File:BBC 454 BLOCK NOTCHED BORES.jpg]] <br style="clear:both"/>
The small diameter flywheel is 12-3/4" in diameter, and has 153 teeth. Starters for small flywheels have two bolt holes which are parallel to the back of the block.
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[[Image:Chevy_starter_1964.JPG|thumb|350px|left|Straight across bolt pattern for the small 153 tooth SBC flywheel/flexplate]] <br style="clear:both"/>
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Most Chevrolet blocks are drilled for both types of starters. If you are changing the diameter of your flywheel, you can convert your present starter to fit the new flywheel by installing the appropriate starter nose.
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{|
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|[[File:Block starter pad.jpg|thumb|370px|Chevy starter bolt hole locations for 168 tooth (black circle) and 153tooth (red circle) flywheel/flexplates. Blue circled hole used by both]]
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|[[File:STARTER_MOUNTING_HOLES_BLOCK_PASSENGER_SIDE.jpg|thumb|380px|Chevy starter bolt hole locations for 168T and 153T]]
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|}
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===Big block===
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The 396/402 and 427 ci BBC engines were internally balanced. The 454 can be ID'd by its balancer having the inner hub cast with a counterweight.
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[[File:Bbc454 oem balancer.jpg|300px|left|thumb|BBC 454 OEM balancer. Note inner hub counterbalance]] <br style="clear:both"/>
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===BBC external cues for 2- or 4-bolt bottom end===
 
===BBC external cues for 2- or 4-bolt bottom end===
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[[File:Bbc 4-bolt vs 2-bolt fittings id.jpg|550px]] <br style="clear:both"/>
 
[[File:Bbc 4-bolt vs 2-bolt fittings id.jpg|550px]] <br style="clear:both"/>
  
 
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[[Category:Identification and decoding]]
 
[[Category:Engine]]
 
[[Category:Engine]]
 
[[Category:GM]]
 
[[Category:GM]]

Revision as of 19:34, 17 May 2012

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