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#1 |
![]() Join Date: Jan 2006
Location: Decatur, AL
Posts: 1,112
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So starting a new thread as I posted this in my other long thread I have going but not getting much attention. So unexpectedly, I had to pull my stock headers and Flowmaster cat back system to replace my motor mount and C-Beam plates.. I am going to bite the bullet and replace the headers with OBX because that was a planned future upgrade but the stock ones being such a PITA, I have them ordered now, can't spend the money on the Corsa catback that I want right now, so I need to mate the OBX's to the old Flowmaster, seems there is an issue on the right side, a prior modification? What do I need to do to get the two connected, car is up on stands and really can't get it to a trans shop, help and part ideas would be appreciated. Also, do I reuse the OE header stud that does into the oil gallery (resealing of course) I have new header bolts ordered. (seems the right exhaust has a flange added?) Thanks.
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Corvette95 Registry and Forum (*************) 1989 C4 Conv Wht/Gry Auto Hardtop Top Flight SOLD 1995 C4 Coupe Purple/Blk 6 Speed 1989 C4 Conv Wht/Red Auto SOLD 1996 C4 Conv Black/Tan Auto SOLD 1994 C4 Coupe Wht/Blk SOLD 1995 C4 ZR-1 White/Gry #278 Dual Dunn Head SOLD 1986 C4 Coupe Black/Red 4+3 SOLD 1990 C4 ZR-1 Red/Red #0454 |
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#2 |
Join Date: Oct 2004
Location: Folsom CA
Posts: 1,648
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Flange has definitely been added. The stock configuration for a '90 is flange on drivers side and slip fit with a clamp on the passengers side.
You have two options. Install the headers and drive it with open exhaust to a nearby muffler shop. Although this would be fun, your local constabulary would take offense if they caught you. Install the headers, get out your tape measure and digital camera, and calculate precisely how much to cut off the flowmaster catback, and have flanges welded on. Then pray to whichever deity appropriate for such endeavors, and bolt it up. Hopefully it will be close enough so that you can then drive it down to the muffler shop for adjustments it will definitely require. Of course, you could just install the headers and then have it towed on a flatbed to the muffler shop, but where would be the fun in that? Crabs
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TomC '90ZR1 #792 Honorary Pirate [B]If it ain't FUN, you're doing something terribly WRONG. [/B] Last edited by tccrab; 12-05-2020 at 10:59 AM. |
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#3 |
![]() Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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That flange on the right exhaust manifold is OEM stock. I can show you pictures of two I've done in the past few years that are identical. It's the OBX headers that are not designed to mate with the stock exhaust. I did OBX headers on my car and had the exact same issue. You have to have an adapter piece fabricated for the headers to mate with the flange on the exhaust. Similar to what your seeing on the OEM manifold. Or... you can cut the flange off the exhaust and use commonly available exhaust pipe adapters to mate the headers to the exhaust. I've done it both ways.
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90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. |
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#4 | |
![]() Join Date: Jan 2006
Location: Decatur, AL
Posts: 1,112
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Corvette95 Registry and Forum (*************) 1989 C4 Conv Wht/Gry Auto Hardtop Top Flight SOLD 1995 C4 Coupe Purple/Blk 6 Speed 1989 C4 Conv Wht/Red Auto SOLD 1996 C4 Conv Black/Tan Auto SOLD 1994 C4 Coupe Wht/Blk SOLD 1995 C4 ZR-1 White/Gry #278 Dual Dunn Head SOLD 1986 C4 Coupe Black/Red 4+3 SOLD 1990 C4 ZR-1 Red/Red #0454 |
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