[Sox]

Originally Posted by castellan

One thing you must do if you have messed with the exhaust is to get it tuned for it, as you will only loose power by exhaust alone and that's a fact !

Ah no, it's not.
Most of these Falcons run on the rich side standard, therefore improving exhaust flow, actually leans the AF ratio out by small amount, getting it closer to 'correct'.
Therefore producing more power, usually right across the range with a good system.

If you want more torque change the cam, as that's the heart of the engine that rules such things.

True enough, however there are many other things which can be changed to enhance certain rpm ranges.

Much of this has already been pointed out.

Originally Posted by Crazy Dazz

Gotta be honest, most of the above suggestions may improve top-end power, but won't do much for low-end torque.

Which is why I suggested a tri-y header with a smaller primary pipe. This will improve torque at lower revs, without a doubt.

A shorter diff ratio will effectively give you more torque at the back wheels, but at the expense of cruising economy.

Not by much though, I've shortened diff ratios on probably 20 different Falcons over the last 25 years.
Many of them had almost no change in economy.

You can tweak it a bit with a tune, but keep in mind that all you're really playing with is ignition and fuelling.

Sure, but pour 98 fuel in, and give it some more ignition advance, and watch those wheel spin.
A good tune, can make quite the difference.

Originally Posted by castellan

Carby engine all's ok but EFI you loose power, I had a new VS 5.0L 179KW commodore manual and a mate bought one just the same and we had runs in 3rd gear before he did the exhaust and mine was just a bit quicker then his, but when he got the full exhaust done, extractors and 3inch system he came out for another run and I hosed him off no problem, he thought he had more power because of the noise before hand, but the fact is he had lost power, he was so spun out at the time, that I just said to make him feel better that I had mine chipped and he totally believed mine had been chipped. but when he got his chipped he just blew mine away into the weeds.
Truth be tolled I wanted him to get it chipped and all so I could see the difference, I think he was only set on going for exhaust before that.

And another VT 5.0L SS had a full system and the other VT 5.0L SS was stock, fact is the stock hosed off the full system one that was not chipped.

Without knowing what kind of headers and exhaust was fitted, it really doesn't tell us much.
The header pipes may have been too big, the system might have been too big, there's too many variables here to make the blanket statement you made.

We're also not talking about a Commodore, rather a Windsor powered XR8, of which there's possibly hundreds on this very forum which have made nice gains just by changing headers and exhaust system.
Myself included.

Some poor bugger thinks exhaust works just like the old carby fed do is totally mislead.

Actually, without re-jetting a carby, it's more likely to drop power than an EFI system.

The fact is, both EFI and carby's need tuning to to optimise for every change, though EFI is a little adaptable without a tune.