Aussie quench heads - Vintage Mustang Forums
Vintage Mustang Forum
HomeForumGalleryClassifiedsAbout UsAdvertiseContact Us
» Auto Insurance
» Featured Product
Go Back   Vintage Mustang Forums > General Discussion > Mod and Custom Forum
Vintage-Mustang.com is the premier Ford Mustang Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools
Old 07-21-2008, 04:12 PM   #1 (permalink)
Member
 
Join Date: Mar 2005
Location: Woodinville,WA
Posts: 98
Default

How much better are the Aussie heads for the 351C vs. the 4v vs the 2v? Im looking into purchasing a set of Aussie's but wonder if there are better out there. Like the aluminum heads etc.... any info would be greatly apprecieated. Im not made of money thats for sure and don't want to make a bad purchase because of lack of info.
tschwendeman is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-21-2008, 07:39 PM   #2 (permalink)
Senior Member
 
Join Date: May 2005
Location: Charlotte NC
Posts: 1,038
Default

Get you a good set of the quench 4V heads and a dual plane intake.
The Aussie heads are OK but really don't flow a a lot of air.
Jsams is offline   Reply With Quote Quick reply to this message
Old 07-21-2008, 08:17 PM   #3 (permalink)
Senior Member
 
Grabber70Mach's Avatar
 
Join Date: Jun 2007
Location: Southern Maryland
Posts: 1,328
Default

You might want to check out some of the info here. Lots of good 351C tech.

http://www.network54.com/Forum/119419/
Grabber70Mach is offline   Reply With Quote Quick reply to this message
Old 07-22-2008, 07:50 PM   #4 (permalink)
Senior Member
 
ultrastang's Avatar
 
Join Date: Sep 2006
Location: Arkansas
Posts: 752
Default

If you are not building a dragstrip or opentrack car, then the Cleveland 4-V heads will not perform as well on the street as the Australian 302 heads. The 4-V Cleveland heads need a lot of engine RPMs to really make use of and support the high flow requirements of the large 4-V head's intake and exhaust ports and its very large valves.

The "Clevor" swap was popular prior to the early '90s --mainly because, other than 289 HiPo heads [nearly inpossible to find, and expensive if you did], or '69-'76 351W heads, there were really no performance heads available for small-block Fords before that time.

With the advent of the 5.0L Mustangs in '87 though, the performance market opened up to many manufacturers producing very high performance heads --both in cast iron and alumium, for the small-block Ford crowd. At that point, the Clevor swap or the use of [old] factory performance heads sort of faded away.

The stock 351 Cleveland 2-V heads have 76.2cc combustion chambers with 2.04" I and 1.66" E valves. 351C 4-V [and '70 Boss 302] heads have 62.8cc's with 2.19" I, 1.71 E [2.23" I, 1.71" E for '69 Boss 302 heads].

The Australian 302 Cleveland 2-V heads have 62cc quenched [closed] combustion chambers, no smog bumps in the exhaust ports and the intake ports are 10% larger than the American 351 Cleveland 2-V heads.

There is no "2" or "4" cast into the corners of the Aussie heads [near the valve covers] like you'll find on the 351C 2- or 4-V heads.

There is, however, one identifier on the Aussie heads that you won't find on the 351C heads; There is a casting alpha-numeric under the #2 cylinder's exhaust port on the head that should read, "AR-D1AE". The "AR" is exclusive to the Aussie head and is not found on the U.S.-produced Cleveland 2-V heads.
__________________
My current vehicles:
1968 Mustang notchback
1990 Mustang GT
2003 Mach 1
1969 F-100 short bed Ranger pickup

Producer of Mk VII and SN-95 Rear Disc Brake Conversion Brackets Since 2002.
http://www.ultrastang.com
ultrastang is offline   Reply With Quote Quick reply to this message
Old 07-23-2008, 12:28 AM   #5 (permalink)
Senior Member
 
Join Date: Feb 2004
Location: Orlando, FL
Posts: 2,392
Default

Back in the 80's the Aussie clev heads got a lot of press in car mags as if they were best thing since sliced bread. They offer only 1 real advantage over the U.S. 2V heads, a small quench style combustion chamber. As popular as Clevor conversions were at the time, the biggest complaint about using 2V heads was the detonation prone chambers made it hard to build in any decent amount of compression and run it on pump gas. As far as port flow numbers, they are very similar to U.S. 2V heads, which isn't all that bad for a street driven 351. They are about the same as the low end of aftermarket aluminum windsor heads.

For what the castings cost, plus the work to rebuild them for a performance engine, the benefit of the quench chambers over U.S. 2V heads is questionable and certainly makes the use of 4V quench heads a more realistic option. Contrary to wide spread opinion, the 4V heads can work just fine on the street and you don't have to rev it to 7000 rpm either. The key is proper cam selection and adequate compression for the cam. Just look at the '71 Boss, the fastest 1/4 mile of any of the Boss's and the main difference between that and other 351C's was the solid lifter cam plus 11:1 compression. The '70 4V was no slouch either, and both of these engines used 4V quench heads that had the same port and valve sizes. Later 4V engines that had lower compression for emmissions regs are IMO the main reason the 4V heads have the poor rep for street performance that they do. If you really want to improve performance over the U.S. 2V heads and the 4V seem like too much port size for your plans, go with one of the aftermarket C heads like the CHI 3V.
__________________
"It's not having what you want, it's wanting what you've got!" - Sheryl Crow
Rickmaan is offline   Reply With Quote Quick reply to this message
Old 07-23-2008, 07:03 AM   #6 (permalink)
Senior Member
 
Join Date: Nov 2004
Location: Sweden
Posts: 1,332
Default

Also, keep in mind that the intake ports of Clevelands are about half an inch longer than those on Windsor heads (about 5.5" vs. 5"). That means that a 225 cc 4V Cleveland has a similar port cross area (which is what's important, not the volume) as a 205 cc Windsor head, which is a little big, but not huge for a street driven 351 CID engine.

2.19" valves are not all that big for a 351 CID engine either. They're about the same as 1.88" valves in a 302 (per cubic inch of displacement).

If you scale down both the valves and the ports, then a 351C 4V heads on a 351 becomes the equivalent of a 175 cc Windsor head with 1.88" valves on a 302.



Helmantel is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 03:36 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.