Dan,
this won't need resizing as it's the male end I'm cutting.  It will just slip into the Y and Bob's ya uncle.

Once you get it cut to the right length, take it to a local muffler shop. They can expand the end for a proper sleeve fit. I once made a template on masonite for the long middle pipe, took it and a length of straight galvanized pipe (fencepost) to my local Midas shop and they did it up while I waited. Cost? a box of donuts the next time I went by. Since Tim Horton's was just 3 or 4 doors down, I paid my 'bill' promptly. (I don't think they even expected me to come across.)

problem solved thanks to Nick Rogers.  I have an rc 40 which is designed for LCB manifold. I've got a maniflow. The center pipe female end is designed to fit the LCB.  I need to cut about 10" off the front of the center pipe to make this work.  That would be the side of the center pipe with the bend.

it's not the short pipe and maybe like the long one.  I don't have a computer at work.  It would be nice to have some dimensions on these. I"ll measure mine.

the over lap is a good 10" and it appears that I need to cut the center pipe before the bend.

Still picking brains before I cut it. It's not rocket science but don't want to ruin a good stock part if I've overlooked something.

Only one end is split on a genuine RC40 centre section as it is designed to slip over the freeflow manifold.


The centre section for an LCB manifold isn't kinked and isn't split as it goes inside the LCB.

Which pipe do you have ?

I'm guess you have the one for a freeflow instead of an LCB, and the instructions tell you to cut the end off as it's the wrong size and shape altogether...

https://www.minimania.com/part/RC40-001/Austin-Mini-Down-Head-Pipe-For-Two-Box-System-From-Standard-Header
https://www.minimania.com/part/RC40-002/Rc40-Short-Down-Pipe-For-Twinbox-To-Lcb-Manifold

Can you perhaps remove one piece and have it enlarged so the other slips in?

the center pipe is split at the rear as is the front of the rear twin box.  And they are the same OD.  One will not slip into the other.
and the pipes are mocked up with the front piece Y secured on the maniflow header. With the center pipe slipped on the Y, and hanging properly, and the rear section of two boxes mounted on the rear subframe, there is an overlap.  I'm Ok with cutting it myself, just wondering if someone had written down a measurement.  I'll write it down and post it here so others can benefit.

Possibly, I got the wrong center pipe when it was shipped to me.
Possibly, the center pipe I got was for a single box RC-40

I didn't have to cut a thing. I do know the hanger on the front of the rear sub frame didn't line up well, but every other aspect fit perfectly.

It doesn't.

I don't know how many RC40s I've fitted, but it's well into double digits and they are the best fitting system bar none.

How do you know if it needs to be cut??  

The problem is that they last so long that you (I) forget what was involved in the initial fit   I do remember that Keith Dodd was upset when I asked him for a hacksaw when I bought the one I have.  There was no way it was going to fit in my carry on luggage without a bit of adjustment.  Once I explained the issue he went and got me a plain middle and back box.  I then took the bits to an exhaust shop and told them to make it fit.... which is what they get paid for so there was no drama.

I did have to get a bit welded in when I moved mine from the S to the Traveller so I'm pretty sure they don't give you extra just in case.  Not all exhaust manifolds/downpipes are the same so maybe yours differs from the one the designer used??

I would make sure the exhaust manifold is fitted, then bolt the RC40 in place and work out what has to be done to make a neat join.  You may find the main pipe has to be "adjusted"/bent to ensure a nice fit with proper clearance around things like the remote shift (if indeed you have one).

IMHO its something that is tailored to fit rather than just measured/cut and bolted on..

Cheers, Ian

Anyone know why the center section needs to be cut at the back end?  I've got a 2 box system, and wondering if the center section is made for the single box and when used with the twin box requires cutting.

and, does anyone have an exact measure from the rear as to how much to cut off? 

measure 3x cut once.