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#1 |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
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POLL: OEM exhaust manifolds on your 71-72 402 BBC
Attempting to discover common ground....Possibly establish the part numbers (maybe date codes too) for the original exhaust manifolds.
Note, it's not necessarily what's shown in the 1979 parts catalog, because they may just be replacement parts. Also, 3989343/3989310 is all over the web, but I believe these are for passenger vehicles, and they still might not be the original parts. Also, the same part number can show for those with or without emission ports. I'll start: 1971 C10: LH 3994045 - No Emission ports RH 353030 - No Emission ports Don't know the date codes. Incidentals: I believe the LH was replaced when the engine was rebuilt in 1993. I seem to remember the original busting when I removed it. Can't say the new one is the same as the old.
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Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 Last edited by 71CHEVYSHORTBED402; 10-21-2015 at 12:17 PM. |
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#2 |
Senior Member
Join Date: Jul 2004
Location: Sweden
Posts: 833
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
Mine have the exact same numbers, 71 C20. I believe it had the original 402 engine in when i bought it. It still had the heat stove and pipe for example, absolutely no guarantee for it to be the original engine though. All the searches I do for those comes up with 73-76 454 police for 353030 and 73-75 454 police for 3994045.
If that is correct non of us have the original exhaust manifolds.
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Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon |
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#3 | |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
Quote:
Without A.I.R. 3994045 LH 333846 RH (3916178 to 3994046 to 333846) With A.I.R. 343787 LH 353030 RH Like I was saying, the same part number shows on some with and without A.I.R. For example, 353030 comes both ways. Leads one to believe at least some are replacement parts. I believe the emission versions were added in 1972. As an example, I suppose it's possible the 71 came stock with a 353030, no ports. Then they started to produce the same under the same part number, with emission ports, beginning in 1972...........I believe I've seen the 45 with and without ports as well.
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Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 Last edited by 71CHEVYSHORTBED402; 10-19-2015 at 11:24 AM. |
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#4 |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
Mystery exhaust poll..........TTT.
__________________
Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 |
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#5 |
Senior Member
Join Date: Jul 2004
Location: Sweden
Posts: 833
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
I did not mention in my first post but mine are also w/o air.
__________________
Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon |
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#6 |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
I have a 3994045 that's off a truck. It Reads L71, which may be December 1971.
I see 3994045 and 353030 everywhere. Coming to the conclusion these came with the trucks. But I also have a 3994046 that's off a truck. Don't know the code or history yet (it's not L71), but #3994046 looks awfully close to #3994045, if you get my meaning.
__________________
Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 |
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#7 | |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
Quote:
Still looks to me 3994045 and 3994046 are a matching pair. Not to say 3994045 and 353030 isn't. http://chevellestuff.net/qd/exhaust_casting_by_year.htm
__________________
Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 Last edited by 71CHEVYSHORTBED402; 10-21-2015 at 07:32 PM. |
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#8 |
Senior Member
![]() Join Date: Jan 2013
Location: Monrovia CA
Posts: 453
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Re: POLL: OEM exhaust manifolds on your 71-72 402 BBC
Are the 1973 interchangable with the 1972 ?
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