Exhaust Flanges

Where would I be able to find exhaust flanges?  I can't seem to find a place that sells 1 1/4" flanges..  
I Want to make a custom exhaust.

While on the topic I also need to know what's the name of the flippy flappy that are on some tractor stacks, that would help find me what I'm looking for haha.

I usually us the stock exaust flang or make one. And the flippy flappy thang is a rain cap for tracters.  Tracter supply has em.

You will have to make a new flange or pay out the butt for one. You can find cheap hole saw kits for like $16 on eBay, or just buy a name brand in the size you need. The find a piece of 1/8" thick steel and drill away.

there are many names flappers, tinker, rain cap.....

I always get big washers at tractor supply to use for flanges. Various sizes available and they're pretty thick. All you need is to set your gasket on, mark the holes, and drill. I forget what size these are, inside diameter is just about perfect for the pipe. About 1 inch I think. You might need to cut an edge off somewhere if your carb is bolted too close or there is some other obstruction of course.