Hey guys what's exactly is the skinny on the Aussie heads? and what are the differences between the Aussie heads and the 2V heads?

 

'Aussie' 2v heads were designed for use on a 302C, (a destroked 351C like the 351m is a destroked 400), and to ensure a decent sompression ratios (around 9.5:1), Ford descreased the size of the combustion chamber. Hence, the 'aussie' 2v head is identical in every way, shape and form to a US 351C 2v head (or even an 'M' head for that matter), except for combustion chamber design, which is similar to that found on early model 4v 'quench' chamber heads, but even a little smaller (i think 3-5cc's or so, not quite sure). Hence, putting a set of 'aussie' heads onto a stock 351C 2v or even an 'M' will raise compression 1.6 or so points, ie even more than putting 4v quench heads on, and because of the quench effect, detonation is kept under control. I have a set of these heads in my garage, but recently aquired some 4v quench heads and will be using them instead.
The aussie 302C heads (we call them that here because we also got 351C 2v's) are a good modification on any otherwise stock M or 2v cleveland motor, although I've heard that in the US they can be a bit pricey. Put it this way, it is a common modification here for people to DITCH their 4v heads andfit ported 2v closed chamber (302C) heads, along with fitting them with 4v valves, giving higher copmression and a more usable power band for street driving.