[DeTomaso] 2V heads

[mark skwarek]

Dan,
  My short block seems not to have any issues at this time. What I might do is to stuff the intakes a bit on my current heads, get a new intake and port match it.. This should hold me for an ORR or so. 
   
  Idealy I'd like to run up to 6500 RPM.
  Mark

Daniel C Jones <daniel.c.jones2 at gmail.com> wrote:
  > Does anyone have any experience with the Aussie closed chamber 2V heads?
> What RPM are they good to? Is there much improvement over 4V heads in a
> stock '73 engine.

I had a stock '74. It's biggest problem was the very low compression
(advertised at 8.6:1), having both open chamber heads and dished pistons.
Putting a larger cam in one of those engines just bleeds off cylinder
pressure you don't have. Adding the small chamber Aussie heads gets
you the compression without having to swap out pistons.

> One advantage (assuming it's used correctly) is that the closed chamber
> heads, having a much smaller combustion chamber than the open chamber,
> will boost your compression ratio significantly.

Yup. That extra compression works across the RPM range and feels
like extra cubic inches.

> Anybody happen to know what the Ausiie heads compression ratio would be
> for a stock 73-74 engine? and for a 71-72 engine? Even approximate would
> be of help.

About 10:1 with dished pistons and 11:1 with flat tops. You can
run either with pump gas with a bit of cam overlap.

> If you choose your components wisely, you can build a monster motor with
> these heads (like Charlie McCall's, or Larry Stock's.) But if you want
> to spin at 7000+ rpm, early closed-chamber 4V heads are probably a better
> bet.

Yes.

> Personally, if I didn't already have a set of Aussie heads in-hand and
> wanted to swap, I would probably install Edelbrock heads, which give all
> the advantages of Aussie heads and more, plus lighter weight, and not
> much more cost.

The Edelbrock heads are on the order of $1800 assembled. You should
be able to put together a similar set of Aussies for $800.

> Note that 2V American heads (open chamber) suck. They make great wheel
> chocks however. :>)

Real US 351C-2V heads have very similar ports to the Aussie 2V but you
don't get the compression boost.

> I am planning on pulling the engine to see in if has the Ford 2pc valves
> and if so replace them.

Before you the engine, pull a valve cover and look at the keepers. If
they butt together without a gap, it's the stock keepers which means
the stock valves are probably still in place. If there's a gap, someone
has installed different keepers so it's possible (but not certain) the
valves have been changed. Many but not all aftermarket valves are non
magnetic, so you can do a quick check with a magnet too.

> I'm just trying to explore what can be done for a modest outlay to
> improve the performance. Ultimately I would like to replace the
> engine with one that make around 500HP.

Sounds like what I did. I bought a low mileage '74 Pantera L
with a stock engine. I swapped on the Aussie heads, a Weiand intake,
matching headers and a mild cam and had fun while I acquired the
parts to build a big stroker engine.

If your engine needs rebuilding, you might consider jumping right
to a stroker kit. The SCAT cast kit is around $1300. The extra 50
cubes will do wonders for the 4V heads and it's pretty easy to
make 500 HP. I just dyno'd one at around 485 HP through mufflers
with a fairly mild cam (peaked at 5500 RPM). A bit more compression
and/or cam timing would have put us over 500 HP.

Dan Jones
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