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Closed Combustion Chamber vs Open Chamber

  
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Closed Combustion Chamber vs Open Chamber

 
FB338 FB338
New User | Posts: 7 | Joined: 12/11
Posted: 12/31/11
04:03 PM

I'm new to your forum and have a few questions. I'm in the middle of a rebuild, stroking a 400 block to 461ci. I have a set of iron heads #17 that I was running on a 350 that Bulter Perf. ported/ added bigger intake 2.11 /exhaust 1.77 valves. They are flowing ~242cfm @ 0.500. I came across a set of #670's Closed combustion, Question, whats the difference in performance with the open chambers (#17's ) vs the 670's Closed, if ported? Would it be worth any gain to work the 670's?

Thanks  

Pontiacman8 Pontiacman8
Moderator | Posts: 5771 | Joined: 02/08
Posted: 12/31/11
04:20 PM

I would stick with the open chamber heads as the closed chamber larger valve heads have valve shrouding issues.

I would also watch how much CR you run if using pump gas.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

FB338 FB338
New User | Posts: 7 | Joined: 12/11
Posted: 12/31/11
05:26 PM

Thanks Pman,
I 'm going with 9.5:1 CR, using Ross custom piston ~25cc dish with the heads at ~73cc should give me 9.5:1... I hope.  

Pontiacman8 Pontiacman8
Moderator | Posts: 5771 | Joined: 02/08
Posted: 12/31/11
06:11 PM

Your welcome anything else just ask.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8