Mystery valve... came out 78 400 th350

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CorvairGeek

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That's from a CCC system, or from a truck with HD emissions with the little controller box on the firewall (possibly).
 

CorvairGeek

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Computer Control Command is the GM name for the electronic feedback fuel system starting (U.S. Federal emissions) with cars in 1981 (similar for Cali in 1980).
Heavy Duty emissions is kind of a misnomer. They were easier to meet standards, for higher GVW trucks that were phased in over the years.
There were some non-computer controlled HD emission trucks with electronically controlled A.I.R. systems. The box looked like this. I'm pretty sure I lifted this image from this site. I have seen some of these myself as well.
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bucket

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Computer Control Command is the GM name for the electronic feedback fuel system starting (U.S. Federal emissions) with cars in 1981 (similar for Cali in 1980).
Heavy Duty emissions is kind of a misnomer. They were easier to meet standards, for higher GVW trucks that were phased in over the years.
There were some non-computer controlled HD emission trucks with electronically controlled A.I.R. systems. The box looked like this. I'm pretty sure I lifted this image from this site. I have seen some of these myself as well.
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My '86 C20 454 Suburban had a non-computer controlled engine and it had dual smog pumps. It had that box on the firewall.
 

CorvairGeek

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My '86 C20 454 Suburban had a non-computer controlled engine and it had dual smog pumps. It had that box on the firewall.
Someone has that monstrosity for sale on our local CL. I imagine the manifolds ran shockingly hot.
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bucket

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Someone has that monstrosity for sale on our local CL. I imagine the manifolds ran shockingly hot.
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Lol, damn! I didn't remove the manifolds, but I have the rest of the garbage. I've never found anybody willing to just take it for free.
 

MikecLA

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i go with bucket. smog diverter valve. probably could ebay it. i was looking at a truck to buy but the guy pitched all the smog i would need for CA.
 

HotRodPC

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CCC? What is heavy duty emissions?
CCC is Computer Command Control. GM's 2nd computer system, (if you don't count ESC as a computer system) but first computer system in trucks. It incorported ESC (Electronic Spark Control) along with a feedback carb with a mixture solenoid. C4 was GM's first computer which was Computer Controlled Catalytic Converter.

That part look alot Fordish to me. And it's missing a cap, either metal or plastic that goes over that thermostic looking part with the spring.
 

AuroraGirl

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CCC is Computer Command Control. GM's 2nd computer system, (if you don't count ESC as a computer system) but first computer system in trucks. It incorported ESC (Electronic Spark Control) along with a feedback carb with a mixture solenoid. C4 was GM's first computer which was Computer Controlled Catalytic Converter.

That part look alot Fordish to me. And it's missing a cap, either metal or plastic that goes over that thermostic looking part with the spring.
i was thinking ford too for a hot minute.
 

Craig 85

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Someone has that monstrosity for sale on our local CL. I imagine the manifolds ran shockingly hot.
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FYI those are the rare '85 1/2 -'86 stainless 4 into1 OEM manifolds.

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CorvairGeek

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FYI those are the rare '85 1/2 -'86 stainless 4 into1 OEM manifolds.

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Makes sense, the EGTs from that setup could be staggering.
 

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