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Exhaust Manifold

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Richard Cooper

Guest
Hi, I want to replace the exhaust manifolds on my 81. They are all cracked and I am not using any of the smog crap so I want to get rid of all those ugly tubes. I can't seem to find the same size manifolds. Will the 1980 exhaust manifold fit on my 1981? They kind of look like shortie manifolds. Thanks in advance.
 
Joined
Apr 29, 2001
Messages
2,141
Location
Rio Rancho, NM
Corvette
1981 HD Suspension; ZN1 Option
Hi, I want to replace the exhaust manifolds on my 81. They are all cracked and I am not using any of the smog crap so I want to get rid of all those ugly tubes. I can't seem to find the same size manifolds. Will the 1980 exhaust manifold fit on my 1981? They kind of look like shortie manifolds. Thanks in advance.

I recall a previous posting about someone using L83 manifolds on the L81 Vettes. Do a search (second level menu bar above next to "New Posts") and see.

GerryLP:cool
 

Peer81

Well-known member
Joined
May 21, 2003
Messages
2,497
Location
Netherlands
Corvette
'81 Black
I thought 80 manifolds are cast iron or am i wrong?
The 82 manifolds are the same "model" but it has a 2.5" exhaust output and the 81 has a 2". Or something like that I recall :)

Groeten Peter.
 
D

Dave L.

Guest
Will the 1980 exhaust manifold fit on my 1981? They kind of look like shortie manifolds. Thanks in advance.
They will 'fit' the engine but you may not be able to use the stock Y pipe at the manifolds.
 

dirtypants

Well-known member
Joined
May 14, 2015
Messages
69
Location
Spokane
Corvette
81 4spd Corvette Blue dark met
what exhaust manifolds did you end up using on your 81

what exhaust manifolds did you end up using on your 81?
gaskets..or not..
issues? tips?
also..since you have removed the smog crap..did you change carb, or distributor, or remove/disconn computer?
anyone else chime in..on similar mods to an 81 350.
thanks
Nick



Hi, I want to replace the exhaust manifolds on my 81. They are all cracked and I am not using any of the smog crap so I want to get rid of all those ugly tubes. I can't seem to find the same size manifolds. Will the 1980 exhaust manifold fit on my 1981? They kind of look like shortie manifolds. Thanks in advance.
 

dirtypants

Well-known member
Joined
May 14, 2015
Messages
69
Location
Spokane
Corvette
81 4spd Corvette Blue dark met
what exhaust manifolds did you end up using on your 81?
gaskets..or not..
issues? tips?
also..since you have removed the smog crap..did you change carb, or distributor, or remove/disconn computer?
anyone else chime in..on similar mods to an 81 350.
thanks
Nick
I will be installing Hooker Headers long tubes 2456-1 HKKR ceramic soon, will let you know how it goes..install from bottom, removing clutch link to block. PIA taking off the heat shields..but done. Using insulated plug wires, with fabric heat shields. I will have take offs orig 1981 manifolds avail soon.
Nick
 

dirtypants

Well-known member
Joined
May 14, 2015
Messages
69
Location
Spokane
Corvette
81 4spd Corvette Blue dark met
Hooker headers now installed on 81

I will be installing Hooker Headers long tubes 2456-1 HKKR ceramic soon, will let you know how it goes..install from bottom, removing clutch link to block. PIA taking off the heat shields..but done. Using insulated plug wires, with fabric heat shields. I will have take offs orig 1981 manifolds avail soon.
Nick

The new Hooker headers are installed on the 81. !! Long tube, ceramic coat..2456-1 HKR, 3 in collector with Hooker reducers to 2.5 in. New pipes all the way back..no cat, a few less bends..opted for no H or X, to Flowmaster mufflers. I had on hand various gaskets..Reflex and Fel-pro but used the gaskets that come with the headers from Hooker as they were the best fit. Yes.on an 81....gaskets. But used small head ARP stainless manifold bolts..note that the orig factory manifolds have a raised boss at the bolt hole and headers do not..so check bolt length against the hole depth, the new ARP bolts are a little shorter. Long tubes fit just fine, no lower at bottom than other "parts". A/C bolts up the same no special bracket needed, but a/c and clutch linkage have to come out of the way, sparkplugs out to do the install (great time to easily change em), and put on fabric plug wire heat shields at the same time. Ceramics should pass heat out of the engine bay better. PITA getting the orig metal heat shields all off as tiny screws on underside are "invisible". Used PB Blaster on all nuts for about a week prior to removal and all loosened OK. Exhaust sound is deeper and louder under throttle, and on this car, with Edelbrock intake, carb, cam, no smog stuff, no computer and new correctly tuned distributor, and true dual exhaust with no cats I can say without doubt that power/and seat of the pants felt acceleration is improved..noticeably with the headers compared to orig manifolds. I am pleased with the muscle car sound, the look, and the performance gain..as said "seat of the pants"..but I am certain of it. So this application is for a not stock, no smog, no computer etc. If you need orig 81 manifolds..I have em..pics avail of new installed..and the take off set.
Nick
 

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