exhaust pipe size
 

I have a 92 F250HD with a 351W and E4OD. I was wondering what the size of the pipe is that comes off the manifolds.

I believe it is 2 1/4.

It's 2 1/2 coming off the manifolds, 3" between the cats, 2 1/2" at the back of the last cat, and then there is a step down pipe that steps it to 2 1/4.

Actually, it's 2 1/2 coming off of the driver's side manifold and 2 1/4 off the passenger side, into the converter. Why? The heck if know, one of Ford's things. Did the same with the 302 as well, but smaller pipe.

I have the HD setup which is one BIG cat. are both of those 2 1/4 coming off the manifolds?

On my HD, it's 2 1/2 into the cat from the driver's side, and 2 1/4 from the passenger's.
I'm just curious of why you're asking? New exhaust system?

I just want to try to improve my gas mileage a bit. I have a bunch of new or almost new 2 1/4 inch pipe, so I can probably do it for the price of some hardware and hangers.