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#1067979 - 09/15/20 12:30 PM Best type of header flange?  
Joined: Feb 2020
Posts: 42
88ssBrent Offline
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88ssBrent  Offline
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Joined: Feb 2020
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Friendsville,Tn
While I'm waiting for my heads im plotting and planning out other things. My plan is to go with long tubes we shall see.

The question i have is what does everyone feel is the best connection type? The plan is to buy a raw set so i can weld in bungs for o2 sensor, do any needed modifications, and get a local shop to do a good coating. I don't want to deal with leaks so what end should I go with? A regular 3 bolt flange, a ball end, or a v band? Is there any other options. I will be doing the ends myself so no labor cost, just parts.

Thanks
Brent

Last edited by 88ssBrent; 09/15/20 01:02 PM.
#1067989 - 09/15/20 09:48 PM Re: Best type of header flange? [Re: 88ssBrent]  
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mmc427ss Online content
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mmc427ss  Online Content
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Joined: Jan 2000
Posts: 4,917
Pottstown, Pa
Anyone who has had a set of headers with 3 or 4 bolt flanges will tell you they can be a real PITA or they are never a problem. I've had several 3 bolt flange headers. Cheap headers, thin steel, parts crush, replace collector gaskets often. The quality/thickness of the flanges, width of the narrowest part of the gasket, how parallel the two mating surfaces are, just lots of variables. Time usually tells when and if they will leak.
The flex at that header collector to head pipe can be a lot on some system.

When you look at the OEM joints they are usually similar to a ball end, use a flange seal, rarely ever leak and stay tight forever. A short and most mid length use a type of ball seal.

Never any experience with the V band. But did try the band clamps on a few projects and found they didn't permanently clamp the pipes together, replaced with U-clamps.
Bob

#1067990 - 09/15/20 10:38 PM Re: Best type of header flange? [Re: 88ssBrent]  
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BadSS Offline
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BadSS  Offline
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Posts: 1,734
Pearl, MS, 39208
I personally prefer using thick, flat, 3-bolt flanges.  I usually tape some sandpaper to a piece of glass from an old picture frame or an old mirror and use that to run the mating surfaces across the sandpaper to be sure it’s a good machined like flat surface (for a really good seal).  I use the wire impregnated graphite header collector gaskets to mate them. 

I don’t have a welder, but I get the flanges welded to the headers, clocked for best access (both flanges bolted together).. Then get the shop (while on the rack) to tack weld the exhaust pipe to the other flange, and tack weld the nuts to the collector flange, then unbolt them and get the shop to weld all the way around the pipe.  Then bolt that back up for them to run the rest of the exhaust.  I’ve never had a collector leak using this process and the nuts tack welded to the collector flange makes easy on and off for later. 

Those 3 bolt slip collector flanges (not welded to the collector) that you see on some headers are terrible and give the old style 3-bolt flanges and gaskets a bad rep (real easy to warp). Even the headers that already have the flanges welded on come out of the box warped/bent half the time. That's why I prefer headers with no collector rings on them.

#1067991 - 09/15/20 11:55 PM Re: Best type of header flange? [Re: 88ssBrent]  
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88ssBrent Offline
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88ssBrent  Offline
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Friendsville,Tn
[img]https://imgur.com/gallery/BKfg3b3[/img]

So the top set are dougs d308. The craftsmanship was great, the fit was not. Plug clearance on stock heads was great but the part circled in red hit the lower a arm mount bad. I could have beat it in 1/2 inch and it would not have cleared. The d308 was 1 5/8" , 16 gauge, with 3/8" flanges. They fit D port heads and were made for angled plugs the price was $520. They were really nice.

The bottom is the one I was looking at trying next its the patriot h8096. 1 5/8", 18 gauge, with 5/16" flanges price is $241. Fits d port heads and made for angled plugs.

Both headers are made by petronix. I worry why the big difference in price. I can't believe that big of price difference just because of material thickness. I wish dougs made the bottom design in 1 5/8". Doug's does make the bottom design in 1 3/4". I thought about calling petronix to see if they could explain the difference in cost and also is there is any way to make the Dougs in a 1 5/8".

Last edited by 88ssBrent; 09/16/20 12:21 AM.

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