Aussie Charger

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Not a bad price for an old car. These were Chrysler's response to the Ford GTHO and Holden GTR XU1

posted by  Wally

Is that really a reasonable price? What year is that?

It's really nice though; really clean...But are 3 carbs really necessary? lol

posted by  chris_knows

Yes they had to have triple webers to get the 280hp (the E49 had 302 hp) which was more than the 340 small block V8 option. It could do 14.8 seconds way back in 1971 and that was with a three speed. The E49 could do 14.4 out of the box. The engine was locally developed/built and was probably Chrylser's best ever hemi six.

posted by  Wally

Hell yeah! :drool:

posted by  SlipKnoT

Wally you live in Australia right?
You guys always got such cool cars. And from the looks of it, your guys' Chargers were far smaller than ours. :thumbs:

posted by  SlipKnoT

It's a funny thing with human nature... you always want what you can't have. Yes the Aussie cars were generally smaller footprints than the US big arsed cars.

posted by  Wally

:laughing: Well you know what they say, "Where theres a will, theres a way".

posted by  SlipKnoT

and you generally have what you don't think you want :mrgreen:

posted by  windsonian

Wally, I don't know anything about this engine, but in the pix that Chris posted, it looks like the intake and exhaust are on the same side of the head. All the hemi 6's I have seen, had intake on one side of the head and exhaust on the other, which straightens the airflow across the cylinder.

What makes this a hemi? Can you explain airflow through that head please?
Inquiring minds want to know.

posted by  jcutsh

A rhetorical query I'm supposing:wink2:

The general arrangement on many of the sixes here in that era was for counter flow heads. I think the idea was for colder climes where there was some advantage in heating the intake manifold for better cold idle, but I really don't know the reason. Of course the Ford six crossflow head made here is prized in the US as a must have upgrade (I know cos I made a motsa selling one :mrgreen: )

I guess a hemispherical head doesn't really care if the valves are crossflow, counter flow, canted, etc as it's more a combustion chamber shape than process.

Here is a bit of a yarn (

posted by  Wally

Would there be any issues with non-homogeneous pressures with that setup? Or does the compression stroke sort that out? I'd have thought that with a cross-flow engine, you'd get a fairly even pressure gradient to get the air in/out, but that one would be a little more complex. But then again, I guess, the valves are (for all intents and purposes) open on diff'rent strokes..... hmmm

sorry, just kinda thinking out loud ... or on the keyboard as it were.

posted by  windsonian

I'm sure there's all soughts of reasons for counter flow (casting ease, production, etc). I never really understood the comment that crossflow flow reduces blow through on overlap, because the bigarse valves were generally close together no matter what the flow design.

Advantages I can think of for cross flow would be the obvious entrainment of residual exhaust gas pocketed across the cylinder during overlap (i.e "crossflow"), more even cooling of the exhaust valve so less radial cracking, less lead oxide buildup, better swirl efficiency, etc. Canting the valves is probably easier too, although I seem to recall the reverse flow hemi had valves at a fair angle to the bore's centreline.

The old heads with one inlet and one exhaust valve had limits on the size and lift. Valve to bore area ratios on these were often 0.22 to 0.25, while twin valve setups can comfortably be up around 0.32 to 0.35. Average flow on single valve heads is pretty poor, although it doesn't stop the aftermarket suppliers sprouting how good their peak flows are on near absolute vacuum.... strange really because invariably someone using these heads will have the mother of all cams that limits maximum vacuum to around 12"hg (terrible dissapointment to some when the dyno, even with the monotonous rigged figures, doesn't "flow" the hp touted. :wink2: )

Production twin valve heads are nearly always crossflow with some sought of pent/hemi chamber. With the pent roof the flame front can accelerate easily into the 30+ m/s, with just a couple of small quench pads and appropriate squish height. With smaller valves the engine can rev harder, has less rotational mass, the heat conduction on the seat/valve is much better and of course bowls/ports are less confined to available cross section. Preheating the fuel/air is no longer a desirable condition with injection, so keeping the intake runners away from the exhaust manifold is beneficial.

posted by  Wally

Yes Wally I suppose it was. There are so many “wives tales” about the hemi, I thought a little of your expertise would be nice. You did well.

The hemi has nothing to do with where the intake or exhaust are located on the engine, as so many people think.

It is totally the shape of the cylinder portion inside the head itself.

Its main advantage, allows for more area to provide larger valves. However, as you so expertly pointed out, those larger valves required extreme canting which required drastic engineering in the valve train.

Many think Chrysler invented the hemi, because they patented the term. Not so, I believe the first hemi came along in about 1903. BMW, Ford and others all produced engines with hemispherical heads.

I believe Fiat had a marvelous little 500cc engine in the 30's with hemi heads.

The six cylinder, which you Aussies built was a great engineering feat. Not only for the heads, but the crank and rods and oiling are excellent in that engine. That engine will accept amazing abuse. A job well done.

Yes, I used you my friend, forgive me, but maybe the little ones learned something. Lol

posted by  jcutsh

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