2 1/2in exhaust question

OK Im soon going to be building my 2.5in exhaust. And was wondering what any of you guys did to get the down pipes to seal up to the manifolds. I was thanking an exhaust donut gasket. Have any of you guys used this? If so do you have a part number. And is there any better ideals?

why? they seal just fine with the flange.

OK so I have an old flange from a mustang. Its 2.5in, I cut the end off and went to see if it will fit. But the Pipping is way bigger then the manifold. I want to start on my exhaust soon. But I don't want have to pay anyone to flare the ends. So I was going to weld the flared end on to what Im making. Here is a pic of what I have. Now what I want to know has anyone else had the same problem and if so what did they do to take care of it. If not what do I need to do.

i could only mate 2 1/4 inch downpipes to my stock manifolds but my exhaust guy easily found flanges that we could use.

just talk to an exhaust shop they should be able to find some.

Fit to the manifold... yup it sure does... goes right over the ball part and right on to the flange making proper sealing next to impossible.... I know I tried it and ended up welding on a 2-1/4" OD to 2-1/2" OD adapter so I could flare the end a bit and seal it onto the ball of the manifold.

If that isn't sealed properly, your going to end up running rich in closed loop because the O2 sensors will be thinking the car is lean and adding fuel, and then you'll wonder why your fuel mileage went to pot.

Fraser

Thanks for the replies. Have you ever tried using an exhaust Gasket(Like a dough nut Gasket)?

Never seen a donut that would work. I've looked. Also, 2.25" flanges seem to be hard to find too. I know Dodge trucks (318/360) use 2.25" flanges on their manifolds.

Donuts are used on most older vehicles (and maybe some newer ones) that didn't come with the ball end welded or cast on.