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AP Exhaust Engine Pipe Flanges

Old May 10th, 2019, 01:22 PM
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AP Exhaust Engine Pipe Flanges

I found some universal AP steel engine pipe to manifold flanges that work perfectly on my 1970 442 engine pipes. They are part # APH-8777 at Summit and only cost $3.99 each, as opposed to $30 per pair from the resto parts guys. They look a little different, but work perfectly. Below I have pictures comparing the Walker #31862 (which is out of stock everywhere I checked), to the AP # APH-8777. The AP flanges require 1-1/2" long bolts. I use grade 8 bolts and never-sieze.

top side

bottom side
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Old May 11th, 2019, 04:09 AM
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Good info. Thanks, this is what I love about the good people on this site!!
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Old May 11th, 2019, 08:29 AM
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Try stainless bolts.
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Old May 11th, 2019, 08:43 AM
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Which way does it go? Is the bottom left image the nut or bolt head side facing up? And I assume you would just flip the summit flange to work?
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Old May 11th, 2019, 01:34 PM
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AP Flanges

There seems to be some confusion about how they go, so I took some installed pics today. The top side (in my orig pics) faces the manifolds on both flanges.

Passenger side

Passenger side looking up from below.

driver side
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Old May 12th, 2019, 10:21 AM
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Clean the manifold and pipe flange. Apply a film of exhaust pipe paste tighten into position.(assuming the whole system has been loosely aligned at this point). Wipe off excess before it drys. Use a thread chaser, not a tap, to clean the manifold threads. Liberally coat the bolts with copper high heat anti-seize. Wipe excess anti-seize.
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Old May 13th, 2019, 07:30 PM
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For the record: there's also bolt-together "split-flanges" that can be installed on an existing pipe that's already been flared. They're a fine solution as a repair for flanges that have rotted out.

I have an Edelbrock "Stainless Steel" Tubular Exhaust System (Shorty headers) on an '88 K1500 pickup. The headers and Y-pipe are stainless, but the flanges were mild steel and rotted away to nothing. There's no way to install a new one-piece flange because the Y-pipe is welded together on one end, and flared for the donut seat on the manifold ends. The part number in the photo is for a 2 1/2" pipe. I think this is a Walker part number.

Last edited by Schurkey; May 13th, 2019 at 07:44 PM.
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