I just took the manifolds off mine today and the y pipe does not have the same ends as those headers, those headers use ball flange collectors and are much longer

 

I just ordered these and have received them but have not had a chance to see how they fit or bolt up. I won't get to this until next weekend as I'm at the track this coming weekend. I'll report on my findings.

Cheers.

 

Well it's good to know they won't bolt to stock pipes. I look forward to seeing if these things are worth the time and effort to install. I would rather just chop off the stock muffler and put something a little more V8 sounding. Not too loud, just a nice grumble. With a 175k on the clock, sometimes changing the way things work on the engine can go in the opposite direction of what was planned.

 

HERE is a video for headman headers on rover

 

Looks good, very clean set up up. Ill need to find a good exhuast shop to rework everything so I can still cram them cats up in there. O2 simulators would be nice to eleminate them forever.

 

The Headmans are a bad idea. The primary diameter is tuned for a hot cam and high-rpm. You will get less area under the torque curve and less power everywhere except over 5000rpm or whatever. Research header design and use any header tuning calculator and you will see the dimensions on the Headmans are basically what you'd want for a mild 350 Corvette motor, not a bloody Land Rover.

Where the Land Rover could be improved from stock is with a shorter collector length, but there's no good way to package such a thing without losing ground clearance. The y-pipe and first muffler are a bit too far back from ideal but there's no where else to put them unless you're building a custom-body/tube buggy or something. One way to make it worse is to use a straight-through design muffler (Magnaflow) which will effectively extend the collector length even farther.

The Rover V8 produces low volumes of exhaust gas from a relatively small (4.0), turning relatively slow (Rover operating ranges), with a fairly low volumetric efficiency (from the mild cams). The gains most 4x4 operators are looking for are in the low and mid-range, not the top-end. The big primary diameters are going to be worse than ones that are a bit too small.

Where I could see it possibly useful is with a *tuned* 4.6 with an aftermarket cam and fuel-injection mods, in a Disco 2 that's oriented toward the street.

 

yeah I was never big on the long tube headers, vid is not my rig just thought it showed a lot, I was looking for a vid or pics of the disco 1 with p38 factory shorty headers

 

I found a wrecked 01 land rover and took the factory headers off, there was a shop in town that took my headers and pumped an abrasive slurry through them and actually enlarged the internal diameters. I forget how many hours it took on their machine but it was mirror smooth and i could use my inside micrometer and measure a sizeable difference.

 

Well moving away from low end torque is not what I have in mind, when I'm back in Nevada in 10 months I will need plenty of low end power. I think I'm just gonna go with the saying, "if it ain't broke, don't fix it".

 

Just thought I'd throw my 2 cents in. for starters these headers will fit pretty much any rover V8 engine. Depending on the the model you might be frigging around with some stuff under the hood but the Rover V8's are all the same....as far as mounting headers is concerned.
As far as the benefits are concerned, I do not have them...yet. But in all my research on these forums its always seems that the guys that have then, love then and feel a difference, with torque, MPG and HP and then it's always the guys that don't have them and have never tried them that are saying they are not worth it.

I don't know either way, but I guess I'll need to try them myself to really find out.
Good luck with the mods and remember, whether it makes a power difference or not, it's always fun to modify and play around with our cheap, low maintenance hassle-free land rovers.