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Discussion Starter #1
Hi, the image below is from one of the latest Performance Fords mags and is done by a local head shop who has a good name for building Clevos, my question arises from another Clevo forum were i was told that this is the Old? way of doing it. It looks a good way to me as it unshrouds the valves on the correct side and keeps as much quench area as posibble. If anyone has pics of a different-better way of doing it, that would be great. Im aiming at 66cc's for around 10:5.1 compression as i believe with a Crane F246 cam ill get away with 98octane with no problems.
Regards Chris
 

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74 XB Fairmont
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No idea as it's completely different to my old 302 closed chamber 2V's. I had pinging with anything less than 98RON and 10.5:1. I ran 38 deg advance.

http://home.iprimus.com.au/bwill/100_1723.JPG

My CHI 3V's are similar to your article. Yet I run the same everything and have raised the comp to 11.2:1 and still get no pinging. I run about 28deg advance as this was recommended by CHI. Don't know what the timing will end up being after a dyno though?

http://home.iprimus.com.au/bwill/100_1766.jpg

Brenden
 

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Discussion Starter #3 (Edited)
Hi Brenden, i actually sent u an email last night on this subect as u seem to have these motors worked out pretty well. Your right about your chambers being a totally different shape to these ones, just wonder which is best? Do u know what cc's yours were? Anyway thanks for help, regards Chris

Update, i just checked my email and yours got bounced, wrong address?
 

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XEesp351 said:
Hi Brenden, i actually sent u an email last night on this subect as u seem to have these motors worked out pretty well. Your right about your chambers being a totally different shape to these ones, just wonder which is best? Do u know what cc's yours were? Anyway thanks for help, regards Chris

I feel nawseous
 

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Ideally put the head on your bare block and scribe the bore onto the head. Failing that, use a head gasket an make the marking slightly smaller (head gaskets have a larger bore size than the actual bore)

I usually unshroud the intake valve around the 9 oclock to 12 oclock position as shown in the picture. Lay this back towards the bore.

Then as shown in Brenx's first picture, there is a bump at 4 oclock which needs lowering and laying back towards the bore centre. The majority of the mixture swirls in through the intake port's long side, and then enters the chamber in an anti clockwise direction (like a cork screw) focused on the area of the chamber that is relieved in the photo.

Aftermarket heads do this, and fill in the gaps with more quench (flat) area around the valves. Open chamber heads lack sufficient quench and have detonation problems as a result.

I dont know if i explained that ok, but hopefully i did.....
 

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74 XB Fairmont
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XEesp351 said:
Hi Brenden, i actually sent u an email last night on this subect as u seem to have these motors worked out pretty well. Your right about your chambers being a totally different shape to these ones, just wonder which is best? Do u know what cc's yours were? Anyway thanks for help, regards Chris

Update, i just checked my email and yours got bounced, wrong address?
From memory the old 2V's were somewhere between 63 and 65cc. I haven't had the 2V's for quite sometime. Clevo owns my old 2V heads maybe he can check if they are still not on an engine?

My new heads are 60cc.

No idea what happened on the email as my email via the forums is correct.

Brenden
 

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Discussion Starter #7
Thanks for help Brenden and Racer, looking at the 2 different chambers they r totally different, ill take both pics to local head shop and see what he recommends, thanks fellas
 

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Old Ford Fan
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Hey all-
may not be on a 302, but take a look on this site for some very interesting chamber mods- http://www.theoldone.com/boss429head/index.html
Its a modded boss-9, but reading over the site, has a lot of very interesting theory- and it appears they aint BSing...Bob Glidden kicked some prostock butt with these heads.
 

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brenx said:
No idea as it's completely different to my old 302 closed chamber 2V's. I had pinging with anything less than 98RON and 10.5:1. I ran 38 deg advance.

http://home.iprimus.com.au/bwill/100_1723.JPG

My CHI 3V's are similar to your article. Yet I run the same everything and have raised the comp to 11.2:1 and still get no pinging. I run about 28deg advance as this was recommended by CHI. Don't know what the timing will end up being after a dyno though?

http://home.iprimus.com.au/bwill/100_1766.jpg

Brenden
Well if youve dropped 10 degrees timming how can u compare?? obviously you would have no pinging. I used 28 on my ute engine with 14.1. with yates heads. Yates have one of the most efficient designed chambers u can use.
 

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Taking away material from the front of the intake valve to get more size will help promote the air lifting of the short turns and make the port go noisey and loose flow after .500 though lift. Also taking away material away from the back of the chamber gets rid of the quench area. SO i have to ask.... why use closed chamber heads if your going to take away the main reasons for even using them?

If your going to take away the quench just use open chambers.
 

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brenx said:
No idea as it's completely different to my old 302 closed chamber 2V's. I had pinging with anything less than 98RON and 10.5:1. I ran 38 deg advance.

http://home.iprimus.com.au/bwill/100_1723.JPG

My CHI 3V's are similar to your article. Yet I run the same everything and have raised the comp to 11.2:1 and still get no pinging. I run about 28deg advance as this was recommended by CHI. Don't know what the timing will end up being after a dyno though?

http://home.iprimus.com.au/bwill/100_1766.jpg

Brenden

Brenden
I was cosidering buying the chi or the other aussie alloy clevo heads and wondred what was your opinion of the ones you have?

Fred
 

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fredmoss said:
Brenden
I was cosidering buying the chi or the other aussie alloy clevo heads and wondred what was your opinion of the ones you have?

Fred
With the untuned results and tests I've conducted myself. They've completely blown away my old $3700 2V heads. Engine idles better, just behaves better through-out. I can't wait to get it tuned. I am a tad annoyed that it's taking so long. Personally the hassle getting them on/in the engine/car is well worth it. Due to mine being untuned I am fouling plugs. The carb needs complete rejet as the heads flow more than the old 2V's did and the poor old 351 can't burn the fuel. I managed to get it right on idle but don't have the equipment needed to redo the jets and get it right.

Although taking longer may mean the CHI manifold will be ready? Was supposed to be ready this month from memory. Can't remember.

Mine are the 218cc 3V's but the way. Not the EM CHI heads. I personally don't think EM Chi's suited my application.

Brenden
 
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