3" frontpipe w/ stock overpipe
 

Yes, I know this is a silly question but that is the task at hand.
Will a 3" front pipe mate to a stock overpipe and seal?

Without me crawling under the car and just trying it, is the flange on the stock OP large enough to seal against a 3" flange? I know a 3" catback seals to a stock front pipe as the car currently has a 3" resonated perrin.

Yes, I'm aware its going to be loud, Yes I'm aware it's not needed, Yes I'm aware it will drone. It's not my car, I just agreed to work on it if Piece A and Piece B will work together in an awkward union of anti reversion.

Short answer: yes.

Long answer: as long as the front pipe is designed to replace the OEM unit without the need to buy extra parts, yes.

-alex

That's my assumption but i'm worried about it leaking.

Should work. Tell em to get a new over pipe, not much use in a new front pipe if that hinky little elbow is choking it. But yeah just be careful when mating them and it should be fine