The exhaust flange is 2.5" ID and the spun cat is also 2.5" ID with 2.625" OD.

I don't have any spare 2.5" tubing lying around to slip into the flange and cat right now, if I just sit the cat on top of the flange and weld will that be strong enough?

 

Maybe if it is welded really well by an experienced welder. It'll probably crack at or near the weld though. The better option may be to use an expander and/or slit the flange to fit. I'd personally wait until I could get a piece of tubing to fit right.

 

Seriously????.......

It would be just like any other exhaust butt weld. Line it up and weld it on.

 

x2.

I wouldn't be scared of a butt weld on exhaust

 

just make sure you have good penetration, and that the exhaust is still rubber mounted so that the vibrations don't cause the weld to crack

 

Thanks for the tips guys, it's my first time welding something besides scrap so I just wanted to make sure I wasn't doing something stupid.

Butt welding the flange seemed like a bad idea at first, but in retrospect it actually seems stronger than a fillet weld on the slip joint.

 

If you trust your welds it SHOUlD be ok if not bring it to a professional welder