we have a set 3964291 heads on a bbc. what is the difference between close and open heads and how do you tell the difference? which one is the better heads?
we have a set 3964291 heads on a bbc. what is the difference between close and open heads and how do you tell the difference? which one is the better heads?
Closed Chambers were OK but now it is more difficult to get Pistons to match. The Closed chambers run 104 to 109 CCs. The Opens have more combustion area around the spark plugs and are 116 to 119 CCs. The Open Chamber are more common and have a lot more choices. Wanna sell them?
The open chambers are better for many reasons. They flow better for one thing. They promote better flame travel for another. Like LeE said, you have more choices for pistons, and the domes for the open chamber heads are more "chamber friendly", and can be made to work real well when building compression. They also respond better to larger valves. All in all, you can make sopme pretty good power with them without a ton of work, but the right cam is the secret.
Top is open chamber, bottom is closed chamber and two different piston configuration!.. Open chamber is the best bet!..
http://www.hotboatpics.com/pics/data..._heads-med.jpg
as they say a picture is worth a 1000 words. i will look tomorrow when i get back to the shop
thank you
3964291....69-72...rect..CLOSED..396, 402, 427, 454, 109cc chamber
Just so you know, those heads are worth $$$. Depending on the date code, they could be worth more on ebay then you can buy a nice set of aluminum heads for. They are the correct casting # for the ls6.
If you are a dummy like me, bolt on some open chamber #781 or #049s and get 3-400 more rpms and speed with the same set up! I sold my 291s and bought three pair of opens! So I'm for selling to some muscle car guy and ebay would net you the most! But, beware, if they match your motor which is also a rare piece, stop! Check your block casting number as well, you may just be messing up, value wise!
this is quite interesting now. i will have to check the numbers. what casting numbers should i be looking for?
this is quite interesting now. i will have to check the numbers. what casting numbers should i be looking for?
SloT , THROW THEM BIATCH'S ON EBAY AS OE CAMARO ,VETTE HEADS AND THEY'LL BRING THEY'RE WEIGHT IN GOLD MANadd another 5-600 to the and you've got yourself a set of alum complete brodix
Posting Permissions
Reply With Quote