Here is a picture of 2 different headers.

One is a KG header I got from Jparker (silver one). The other was given to me by someone to test for fitment on my 1800 which I was told was based on the KG dimensions (white one).

I finally got a chance to compare the two side-by-side and they are very different.

The KG primaries are slightly closer to equal length before the first 'Y' - not a huge difference but noticeable.

The final 'Y' on the KG header is 14" further back. This is a dramatic difference.

Otherwise the clone header is very well made with a beautiful Swain's coating on it.

What difference would this 14" of extra length make?

I'd add some pipe to those white ones. I wouldn't bother putting them on without making the secondaries at least 21" long.

Some clarifications.
KG does not make their own headers, or at least did not last I knew.
They got headers from a european supplier and there were three different versions for the B18/B20. At the point that I stopped getting headers from Europe, KG was changing to another supplier. Although the european 4 - 2- 1 headers were a far better design than the headers available here ( the US ) in terms of performance, I was not happy with the quality ( quality control ) of the headers we were getting. I had to do quite a bit of grinding to make sure they would fit the head bolts, etc., and they would not fit with all intake manifolds, cars setup with negative camber, etc. That is why, among other things, we are now having our own headers made in the US. Its taken a year to get the bugs out of the design and produce a header that has as much of a universal fit as possible without sacrificing performance. We will finally have them in stock starting next week. Everyone who has seen them so far agrees that they are of far better quality than the headers we were getting from Europe.

As to the shorter secondary pipes. There is now a US maker who is offering a cheap, short, header. Ask him to show you his dyno numbers. He doesn't have any. It's easy to make cheap headers, or any part for that matter, if you don't do any testing.
Shorter secondary pipes will move the power up the rpm range and give you a narrower power band - not normally what you want for a street car.

John
v-performance.com

What John said about length and performance...

As for quality of the new VPD headers, I can attest that they are a MUCH better fit than the Swedish ones.

I have a Swedish 4-2-1 on our 1800. I got it from Unitek, and it's identical to the KGT one Cameron got through John. I had to 1) grind away at the flange to get it to fit the head studs, 2) grind away some more on the flange, and also on the intake manifolds, to get them to fit the engine at the same time, 3) have a muffler shop heat and rebend the secondary pipes so the collector wouldn't hit the underside of the car, 4) cut away a bit of upper control arm for clearance, and 5) cut away some of the bellhousing support for clearance.

Even at that, the header could not go into the car with all the studs in the head -- I had to remove several and reinsert with the header in place.

Now I just put one of the new VPD headers on a customer's car (it's the last of the pre-production ones -- the ones now coming out should be better yet). It just bolted up without any fuss whatsoever.

Glad I make my own, it sounds so much easier.

It is, as long as you are only doing your own.

V-performance.com

There use to be an absolute pipe bending guru that lived in my area & made headers & mufflers for about 90% of the race cars & boats here in Australia, but he retired..... He made good 4-1 headers for me at $350Aus/set.(a decade ago). He use to let me buy bends & collectors from him dirt cheap too, I tried not to bother him too much.

Also of interest, We never saw an advantage in 4-1 over 4-2-1 until we spent a day on the dyno trying different mufflers. No turbo type muffler was any good & we found only one specific type of straight through muffler that was good with 4-1 headers.

I don't suppose you know of, or have lying around, any of these headers?

I am in Australia too and thinking about investing in something like this.

A friend of mine may have an unused set, but he propbably wouldn't part with them. They'd probably be little use to you because they are big 1&3/4"OD X 29" long which require a really good head & very big cam to be of any use.

What are you planing to use them for?

General Road use..

I am hoping to make a few small changes to wring out a few more horse power - but not particularly interested in going too far or spending to much.

trying to keep thing relatively standard.

The stock exhaust isn't all that bad for stock to mild engines. If you need a new exhaust system I would lengthen the engine pipes to 24" & add a big exhaust system. Do you have a B18B or B20E car?

By lengthening the engine pipes I'm assuming you mean the dual downpipe? So lengthen them before they split to a total length of 24"? Or something else?

The header shipments are finally coming in. Got 5 of our new headers today and 5 more are due next week. Shayne got his today. Hopefully from this point on we will have a continuous supply.

John
V-performance.com

Let's compare and contrast my experience with Phil's.

1) me too.
2) I didn't have to grind the intake, but did grind the exhaust.
3) me too, despite trying every possible over-the-counter engine and transmission mounts, in every possible arrangement. The engine went into, and out of, the car 11 times before it stayed there.
4) me too.
5) me too.

Even at that, me too.

Aside from all that, and now that I know how to install/remove this particular header, I'm happy with it. And now that I have it, I'll keep it. When I need another, though, I'll go with VPD's offering.

Best,

Cameron
Rose City

Cam,
Reserve judgement until you see the one that's on the way to Shayne. And then let me know if there are any issues so I can make any changes that may be necessary.
It's actually the first of the newest production batch and has some changes
from the ones that anyone else has seen. Shayne should have it
next Friday.

As I told Phil, the way to assure that every header would fit over the studs and dowel pins on the heads was to pick up the flanges from the header shop after they were cut out, bring them back to my shop, fit them onto my head, mark them all, and then cut the proper clearances on my mill. In the long run a hell of a lot quicker than doing it after the header is put together. And then I still check each header when I get it.

The big advantage of these headers should be that you can crank in negative camber and they will still clear the upper A arms.

John
V-performance.com

Pardon me if I don't understand, but can you not furnish them a drawing with
dimensions and tolerances and just tell them that any part that does not meet
the print will be rejected, and if they want it back they will have to come
to your place and pick it up, but in any case you are not paying for it??

Sounds like they want you to fund either their learning curve or their sloppy
workmanship......

(Or have I worked in too many machine shops and reworked too many rejects?)
--
George Downs Bartlesville, Heart of the USA!

And what kind of "pull" do you think you/I have when you are having 20 done for old Volvos when they are doing 200 or 2000 for Chevies and think of doing any for Volvos as interupting their real work and they are doing you a big favor because most owners of old Volvos are too cheap to buy headers anyway.

John
V-performance.com

because most owners of old Volvos are too cheap to buy headers anyway.

That's very true. Part of the reason I love my is it is so cheap to maintain. :)

You might do a lot better selling 1&7/8" OD X 24" long engine pipes rather than headers to the majority.

The problem for me is not selling them, its getting enough of them.

John
V-performance.com

Yup, 'at's me. They must be in it for money, not love....
--
George Downs Bartlesville, Heart of the USA!

Did not mean it personally. Yesterday was just not a good day in terms of trying to get people who normally do things for Chevies to stop and spend a little time on Volvos. Had one machine shop I had been working with for 15 years tell me he was not going to do any more Volvo work because of the setup time involved. Nothing agaisnt me or Volvos he said, just that he was limiting the work he was going to do as he got older and it was just easier if he could just leave everything setup for SBC's.

John
V-Performance.com