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Discussion Starter #1
Does anyone know what size valves and the ccv of the Australian 302 Cleveland heads.

I have a 68 j-code 302 with 58cc chambers.How much improvement if any would I gain or should I just use 351C heads.

(And yes I do know what is involved in putting Cleveland heads on a Windsor block)

Thanx in advance.
 

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Aussie 302C heads

It's pretty much a waste of time to do such a conversion given the fact that 302 cubic inches is not going to give better performance than a 351W would if the same amount of time and money were spent on each. In fact the 351W is better from any perspective in every legitimate way.

But if you must spend time and money on such exploits there are folks waiting to get the cash from you.

The Aussie 302C heads are 57.8CC nominal, meaning they are typically larger and can be milled to achieve that spec. Typical used ones are going to be 60CC.

http://www.geocities.com/infieldg/images/thumbnails/v8aussie302head.jpg
 

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The 'Clev-or' hybrid was considered a good swap years ago. Years before we had the good aftermarket Windsor heads we do now. Almost all of the aftermarket Windsor heads will out-flow a 2V port Cleveland head, and many will outflow a 4V Cleveland head! Then you have to find the specialized Clevor intake manifolds, etc. It just isn't worth it unless you want the "Ahhh, Oooo" factor when you pop the hood. Then again, most people wouldn't know what they were looking at anyway so even that factor isn't worth the extra hassle and $$$ involved with a Clevor.

Get a set of aluminum World Products, TFS Twisted Wedge, Dart, or even a set of cast iron GT40 heads and you'll be ahead of the game. Your intake manifold selection goes waaaaay up if you stick with Windsor heads! Then there is the special piston issue with Cleveland heads. About the only thing you can do is get Boss 302 pistons, and those don't come cheap either!

Do you see where all this is leading?

Stick with the Windsor!
 

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Discussion Starter #4
Thanx guys!

Thanx for your replies to my Aussie head question.It was just a thought as I can't afford aftermarket heads like Trick Flows.

I found some new GT-40 "P" heads for $270/pr.These heads have 60cc chambers.

What are the ccv of my j-code heads?I have 10.5:1 compression with my flattop pistons and would like to keep it around 10.5 to 11.0

Roughly how much improvement will these heads give me in hp and torque?
 

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Remember, the GT-40P heads require special headers due to the way the plugs mount. You can't really guess just based off of "I had these heads but now I have these" but you should get a decent increase by moving to some decent flowing heads.
 

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The "J" code 302 heads are about 60 CC. You can get some serious performance gains by installing 1.94"/ 1.66" valves in those heads and porting the exhaust side.

Better yet save up and buy a set of Edelbrock Performer RPM heads with 1.94 / 1.66 valve sizes. The ones with the larger 2.02 intakes hurt low end on a 302 and are really better on a 351W.

Which gets back to my original statement. Why not just get a 351W?
 

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you could just slap on the 351W heads onto the 302 as well for a cheap way to boost power. keep in mind that the car will lose a bit of compression with those heads though as the chambers are a bit larger. ( im pretty sure about that ) im in favor of the 351W swap. i plan for one as well in the future for the 67 and from everything ive read about it, it doesnt seem like that big a deal at all. Windsor parts are cheap as well. a car can be built on a budget. but the heads are one area that i souldnt have a problem spending a little more on.
 

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Actually 351W heads don't offer any performance gains unless you find a way to compensate for the dramatic drop in compression. Usually this means changing pistons. I did it on a 289 about 25 years ago following the advice in a Hot Rod magazine article. I had the heads milled .100 and the intake angle milled to match. It was not an effective mod for me because it required basically ruining the intalke for use on any other motor.


The other problem with milling the heads that much is you end up with valve to piston clearance problems, limiting the choice of camshaft to a very mild grind.

Also, the only 351W heads with larger valves than a 302 are the ones from 1969 and 1970. They are becoming hard to find in decent shape, typically it takes $750 worth of parts and machine work to make them usable after you pay for the heads. You are then very close to the price of new Edelbrock heads and have passed the price of new GT 40 heads.

For guys who already own a 351W the stock heads are OK but don't blow lots of cash on a crummy pair when aftermarket heads offer so much more performance for a reasonable price.
 
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