[2720r]

I need some schooling on this. I heard years ago that you can get better performance out of a Cleveland engine by installing the Ford Australia version of the cylinder head. Is this true, and what are the limitations or considerations when installing them? Do standard Ford USA 4V intake manifolds work?

Finally, what does a pair of these heads go for bare?

 

[1969XR7Vert]

Hi Randy,

I have Aussie Cleveland heads on Isabel, "302C" they are affectionately called (even though they were cast in Geelong, AU). I understand the Aussie 351C heads are the same in configuration as USA C heads.

Okay, so here is the scoop on the 302C heads. They are just like US 2V heads in every way except the (quench) combustion chambers are the smallest of any C heads, mine CC'ed at 58cc. Stock 351C 2V are in the 74-76cc range.

So what you get by using a pair is compression, too much compression in fact for pump premium. Mine were a true 10.5:1 (which would be like 11.5:1 advertised, read on). I used custom Cometics MLS gaskets made in .066" thickness in order to reduce the compression to a true 10:1 measured using a Katech Whistler (http://www.katechengines.com/motor-sports/services/whistler/http://www.katechengines.com if you would like to know more about that). True 10:1 is on the bleeding edge of what today's pump premium with ethanol can power.

While I was at it I measured a pair of '70 4V closed chamber heads with the Whistler, they came up at 10:1. The advertised specification is 11:1 so that tells you something about advertised CR values.

A 2V 351C in '70 was advertised as 9.5:1, in reality it was probably more like 8.5:1.

The best way to do a true performance engine using the 302C heads is to use dished pistons of the right size to get a manageable CR (unless you are building a race engine in which case they'll work well with flat tops or a slight pop-up). What I did using thicker gaskets is not the best way as it increases the "squish" area (the area/distance between the top of the flat part of the piston and the flat part of the head deck surface on a quench chambered head). Too much squish hurts the flame propagation characteristics that closed chamber heads are desired for. Too much squish can cause detonation problems. I have managed to get away with it since I only increased squish .025" over stock and I have tailored my ignition timing very carefully (see my recent installment in the ECI thread). In a true performance engine you would want to zero deck the block (my pistons are ~.040" down the hole in an undecked block), use a stock gasket and make the desired CR with a piston of the right volume (dish or dome) to get the desired CR. Building an engine this way yields the best flame propagation characteristics the quench style chamber can deliver.

How's that Randy? Probably more than you wanted to know! If you have any questions either post up or I'll give you a call to discuss.

Hope this helps.

Regards,

Bob

 

[1969XR7Vert]

P.S. www.ausfordparts.com sells 302C heads for $380 a pair.

I paid $260 plus $40 (cheap!, FedEx IIRC) shipping for a pair from a fellow in NYS on ebay back in 1/06. Looked up the transaction, seller "mohawk9". From his recent transactions, looks like he is into engine stuff. You might try contacting him and inquiring on the off chance he still has some, I think he had multiple sets at the time.

Bob

 

[2720r]

This does not sound like a bolt-on conversion. So all a set of Aussie heads does for you is increase compression?

 

[Cougar6869]

Better performance, depends who you ask, how the car is set up, and how you plan to use the car. Due to the big block size ports on the 4V heads, they really build torque and HP in the higher RPM range and will feel a little sluggish just driving around town because you're not hitting that mark. Unless however, you have the right selection of differential gears, standard transmission, and cam it'll be more streetable (my cams torque range is 1800-5000). I am referring to the 4V wedge chamber heads. I've read the open chamber 4V heads make better door stoppers.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com

<st1lace w:st="on">USA</st1lace></st1:country-region> 2V heads with the wedge chambers like some of the 4V = better low/mid torque for driving around town. You can still pick up a set with a little effort, but they are getting harder to come by. I had called Powerheads not long ago for Aussie heads and they told me they used to get shipments three times a year, but their source is drying up and no longer have them. I've read that the Edelbrock heads are close to the Aussie 2V heads, but obviously a little more money. They are probably closer to a bolt on conversion you mentioned, but you will still have to replace your 4V intake, possibly your exhaust manifolds. And let's not forget for the Aussie or Edelbrock heads, some new lifters, etc. Also, keep in mind with either a used 2V or sticking with your 4V head... they used to have lead in gasoline and it works as a lubricant. So for unleaded, you'll want to upgrade your valves and stuff too while you're in there.<o></o>
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The key is to do you're research and read up. A few books I've read for info is "how to build Big-Inch Ford small blocks", as well "High-Performance Ford (221 CI to 460 CI) engine parts interchange". You might be able to pick them up at a library if you don't want to buy them. Note that I'm not a master engine builder and there are more guys on here with greater knowledge. I'm just a regular guy who read up on my engine and know more of the basics.<o></o>

 

[1969XR7Vert]

This does not sound like a bolt-on conversion. So all a set of Aussie heads does for you is increase compression?

Yes, Aussie heads are a bolt-on on conversion on a US 2V Cleveland. Bolt-on if you don't mind ending up with around 10.5:1 (true) compression. If you do (and who wouldn't for a street engine?), at least some of what I described above is necessary.

 

[JeffJ]

They also keep up the intake velocity due to the 2v port size...
I have them on a 377 stroker and I have a hard time not spinning the tires with 9.9 compression and a small 215/224 hyd roller cam...

On a 351 engine they are probably the best "stock " head to run.