C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

85 C4 headers question

Old Jul 7, 2003 | 05:36 PM
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Default 85 C4 headers question

I'm wondering about installing headers on my 85. I have AFR 190 heads (pn 1011) with a 7.5 qt. oil pan. Concerned about clearing the plugs and oil pan; noise; radiant heat into engine/passenger compartment; EASE of installation; significant power increase? All opinions welcome. TIA!!
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Old Jul 7, 2003 | 08:20 PM
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Default Re: 85 C4 headers question (GRX)

Do you have angle plug heads, cause you will need them!

If so, with the hookers 2151-1 you will clear fine but I have straight plugs & with the hookers an they are close on #3 & #4
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Old Jul 7, 2003 | 08:23 PM
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Default Re: 85 C4 headers question (ld85)

No, I think they're straight (84-85 had straight plugs).
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Old Jul 7, 2003 | 08:26 PM
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Default Re: 85 C4 headers question (GRX)

Then I would check into headers to clear the plugs better than mine, I can get by but I would do it different next time.

Maybe some others can tell about their setups.
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Old Jul 7, 2003 | 08:27 PM
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Default Re: 85 C4 headers question (ld85)

Do you have angle plug heads, cause you will need them!
Careful! You need "L98 Angle" plugs, not "Angled" plugs.
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Old Jul 7, 2003 | 08:27 PM
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Default Re: 85 C4 headers question (ld85)

Thanks :cheers:
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Old Jul 7, 2003 | 08:40 PM
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Default Re: 85 C4 headers question (GRX)

Hooker 2149, 2151, and 2151-1, all show to fit 1984 up L83s and L98s. I haven't installed any of these, but Hooker says they'll fit either stock head. They are specifically are listed to NOT fit angle plug heads, other than the "L98" angle, as mentioned above. good luck, and...

RACE ON!!!

PS. I believe Hooker specifically excludes the "AFR angle", angle plug heads. If your 190's are the "L98" angle, you should be OK.


[Modified by CFI-EFI, 6:44 PM 7/7/2003]
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Old Jul 7, 2003 | 09:08 PM
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Default Re: 85 C4 headers question (scorp508)

Careful! You need "L98 Angle" plugs, not "Angled" plugs.
AFR told me that 84 and 85 years had the "straight" plug (as I confirmed with my old iron heads). They also said that 86 thru later utilized the "L98 angle".
Weird, so much variation on a simple motor! :lol:


[Modified by GRX, 6:08 PM 7/7/2003]
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Old Jul 7, 2003 | 09:10 PM
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Default Re: 85 C4 headers question (GRX)

....and my stock shorty headers clear the "staight" plugs fine. So, anybody have installation woes? Pros, cons...
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Old Jul 7, 2003 | 09:12 PM
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Default Re: 85 C4 headers question (GRX)

AFR told me that 84 and 85 years had the "straight" plug (as I confirmed with my old iron heads). They also said that 86 thru later utilized the "L98 angle".
Yep, but the L98 headers require the L98 Angle plugs to clear. Or you'll be into mallet territory clearencing the things.
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Old Jul 7, 2003 | 09:13 PM
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Default Re: 85 C4 headers question (scorp508)

Jeepers, so that is my only solution?
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Old Jul 7, 2003 | 09:40 PM
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Default Re: 85 C4 headers question (GRX)

AFR told me that 84 and 85 years had the "straight" plug (as I confirmed with my old iron heads). They also said that 86 thru later utilized the "L98 angle".
Weird, so much variation on a simple motor! :lol:
It's not that confusing. C4's with iron heads (1984, 1985, and part of 1986) had straight plugs, like your old heads. Aluminum headed L98s (part of 1986 and up) use "L98" angled plug heads. BUT, since you have AFR190 heads, you need to check with AFR, to see what angle you have on your part number, 1011, AFR heads. Good luck, and...

RACE ON!!!
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Old Jul 7, 2003 | 10:09 PM
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Default Re: 85 C4 headers question (scorp508)

AFR told me that 84 and 85 years had the "straight" plug (as I confirmed with my old iron heads). They also said that 86 thru later utilized the "L98 angle".


Yep, but the L98 headers require the L98 Angle plugs to clear. Or you'll be into mallet territory clearencing the things.

I have an '85 with stock heads and straight plugs, and the LPE longtubes fit and clear them no problem.. No modifications and still using normal Rapidfire plugs... :confused:
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Old Jul 7, 2003 | 10:10 PM
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Default Re: 85 C4 headers question (MrNuke)

How was the install???? Starter clears fine?
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Old Jul 7, 2003 | 10:12 PM
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Default Re: 85 C4 headers question (MrNuke)

I have an '85 with stock heads and straight plugs, and the LPE longtubes fit and clear them no problem.. No modifications and still using normal Rapidfire plugs... :confused:
Well thats certainly interesting!
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Old Jul 7, 2003 | 10:20 PM
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Default Re: 85 C4 headers question (GRX)

Yup installed form underneath .. I'll post some pics in a minute..
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Old Jul 7, 2003 | 10:22 PM
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Default Re: 85 C4 headers question (GRX)

with the 1985 L98 corvette, you need to use AFR L98 angle plug heads and a/c delco fr5ls or equilavent plugs. The length of the plug is critical so as to not hit the header on 3 of the cylinders.

No clearance problems at all with hooker 2149 or 2151 headers.

And move that f'n o2 sensor to the collector vs the #7 on the hookers.


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To 85 C4 headers question

Old Jul 7, 2003 | 10:23 PM
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Default Re: 85 C4 headers question (reallycoolcorvette)

Guess not always.. :yesnod:







NONE of them are hitting the headers...




[Modified by MrNuke, 10:24 PM 7/7/2003]
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Old Jul 7, 2003 | 10:27 PM
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Default Re: 85 C4 headers question (MrNuke)

Thanks for posting those Mr. Nuke. Woa, there isn't much room in there for much!


[Modified by GRX, 7:28 PM 7/7/2003]
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Old Jul 7, 2003 | 10:30 PM
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Default Re: 85 C4 headers question (MrNuke)

Are you happy with the performance? I mean, considering cost, and noise/heat factors?
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