closed chamber vs open chamber

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tooslow

tooslow

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Some people prefer closed chamber heads, why? They go as far as milling open chamber 906.s closed. seems like a lot of work?

Any comments or advice are always welcome
 
For the quench, and increase in CR, you can run lower octain if you have nice .035 to .040 piston to head quench. I have a set of close chamber heads on a 383 and the difference between the open 906 is night and day. Did you mill the snot out of your 906's or are you still on the fence?
 
BTW not to many are milling 906 closed the price to do that at least in the Chicago area would make it a dumb thing to do when there are a lot of aftermarket heads on the market
 
Easier to offset grind the crank and bring the pistons out of the deck. you also get more cubes. so you increase the CR formula with more stroke. But no matter what you choose its $$$$. If it was me I would add boost. or NOS.

Cut the head and you have to cut the intake and it will never fit another set of heads. and don't forget push rod length for rocker geometry.

The cheapest and easiest would be get some pistons. or get heads.
 
Depends if you have a budget,and a known good existing short block.915's are getting harder to find.(=$$$$).Milling 906's a viable alternative, new push rods/shimming and matching the manifold a P.I.T.A.Depends on your needs,and wanted.
 
Did you mill the snot out of your 906's or are you still on the fence?

You guessed it Im on the fence, I have a set of 906 heads with a nice valve job and bigger valves and correct springs. My machine shop will mill them including intake for $350. I need to learn a little more(new question). I am going to use them on my road racing dodge

I was considering Aerohead , I dnt live far, can pick them up, but they offer open chamber heads,
Will closed chamber make a big difference?
(this is ***** and giggles my 67 cuda 383 project is wear my extra cash is going)
 
I've always used open chamber.

You aren't that far away from me. Hello neighbor.
 
Naturally aspirated=closed
Force induction=open (more room to for boost)
 
If the pistons in your 383 sit at zero meaning flush with the deck then milling them to close will give you a gain, if there down in the hole even .010 forget about quench you would be only be gaining a more compression. I have a set of bare 516 you could switch all your hardware to $60
 
Closed chambers,usually make more mid range torque,and horsepower. At this point,what's the car/trans/gear/engine combination? And,what do you want it to do?
 
Assuming a zero deck motor, all things equal the closed chamber will probably make more power and do it on pump gas easier. JMO.
 
The forum has paid off, learned alot, saving my 906 heads for a supercharger project in the future and picking up 516 closed chamber heads,
thx
 
tooslow said:
The forum has paid off, learned alot, saving my 906 heads for a supercharger project in the future and picking up 516 closed chamber heads,
thx
Click to expand...

Do you have access to some locally? If not, PM me. I have a nice set.
 
I just purchased 440 Source heads for $1064.93 to my door.Nice folks on the phone, surprised I usually do not expect customer service these days
I was going the 516 route but by the time I gave them a clean up, checked them for cracks, seats, milled them, valves?? I was to close to the 440 stealth heads in cost plus I am shaving 50lbs,
. I am going to shave them .025 to get my Compression up a full point and swap over my springs, new locks and retainers

Thanks for your help
 
tooslow said:
I just purchased 440 Source heads for $1064.93 to my door.Nice folks on the phone, surprised I usually do not expect customer service these days
I was going the 516 route but by the time I gave them a clean up, checked them for cracks, seats, milled them, valves?? I was to close to the 440 stealth heads in cost plus I am shaving 50lbs,
. I am going to shave them .025 to get my Compression up a full point and swap over my springs, new locks and retainers

Thanks for your help
Click to expand...


That's where I am if I continue my Coronet project. I think I will come out a little further ahead than you on price, as I have the larger valves already. The guides in my heads are great. The intake seats are great. All I would have is the cost of boring the exhaust seats to the 1.74 size, the valve job and then porting. Still will be close to the 440 Source heads, so I am holding off. It's just really not economical to do head work to cast iron. I have nothing against the 440 Source, but I think if I am able to do this project I am going to hold out for Edelbrocks.
 
Rusty,understand completely. Ported the SBM Eddys.Crustiness, everywhere. The guides,did check fair,the seats all lapped in quickly. Hear the BBM a lot better,seen a couple sets in person,OOTB.(decent).GOOD machine work on iron,comparible to new aluminums.
 
Can anyone post pics of the difference between closed and open chamber?? Seems like a good a place as any for pics...
 
txstang84 said:
Bowl work looks good so far there Rob
Click to expand...

Oh they aren't mine. I found some pics so he'd know the difference. I hope when and if I am able to do mine, they will be made outta some silvery shinier metal. lol
 
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