Need advice on exhaust > header connection

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Jun 16, 2021
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My Car
1973 Convertible, Q code, 4 speed, 3.25, A/C, P/S
1973 351C 4V vert, 4 speed

I installed FPA headers on my car and am about to install a new exhaust. My question is connecting the exhaust to the headers.

The headers end in a 3" collector. The headers included a ball coupling reduced to 2.5". In the attached photos, the outward flanged piece connects to the headers via the 2 bolt flange included. That all bolts up fine.

The 2.5" exhaust includes a flanged end which I suspect bolts up to stock manifolds. The ball coupling reducer fits inside the flanged end of the exhaust fine, but I have no way to bolt in together.

I don't yet weld (though will learn at some point). Is there a way to bolt the reducer side of the header ball coupling to the flanged side of the exhaust without welding? Or do I need to learn to weld real quick?  :)

Any help is appreciated, and Merry Christmas (almost)!




Are these long or shorty headers? Which exhaust kit are you installing? Please include a link if possible. 

The 45° pipe with the 3-bolt header flange looks like it's part of an H-pipe that in intended for a conventional long tube header. If that's your configuration and everything lines up more or less, I'd cut the flange off the 45° pipe and do what ever is needed to slip it into the FPA collector. A grinder with a burr bit should open it enough to allow a slip fit. You can then get everything sorted, mark the 45° pipe at the collector, trim it for a 1/4" overlap and then have it welded. 

The lower flange looks like it has a standard triangular 3 bolt header connector. You will not be able to use that with your FPA headers. You will need to cut the triangular 3 bolt flange off the exhaust pipes. It seems like the FPA connector is 3" pipe, looks a little bigger than the exhaust pipe, but it may just be me. If you want to do this without welding I would get a female/female 3" to a 2 1/2" pipe connector and 2 exhaust clamps. You cut the 3 bolt flange put the 2 1/2" connector to it with a clamp and put the 3" side of the connector to the FPA adapter with the other clamp and clamp it down. This will work fine, but they always tend to leak a bit. 

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Take the pieces to a muffler shop and have them use their pipe expander on the FPA supplied tapered pipe until the pipes will slip together. Have them cut off the tapered end of the 45 degree pipe. I would suggest welding but you can put "compression slits" in the outside pipe and use a clamp. Just an idea. Chuck