What does the combustion chamber size effect?
what is the stock on the L69 engine?

What are heat risers?

What is intake valve diameter and what does it affect?

Is there a valve size that would be too big for a 305 and effect is negativly?

can a head with a 1.250 valve handle a stock cam with 1.6 rocker arms?

 

Compression ratio
58ccthe passages at the center of the head that carry exhaust gasses to the intake manifold; also used for EGRIt's the diameter of the intake valve. Not much more to it than that. It affects flow.Probably.... 2.02" valves will not fit in the cylinder with some head castings, they will hit the top of the block; and even if they fit, they will be right up against the cyl wall on one side, so no flow can occur on that side; in some cases it's possible to get more flow with a smaller valve that still leaves some clearance between the outer edge of the valve face, and the cyl wallI take it you mean 1.25" valve springs.... in which case, it would depend on exactly what "stock" cam you mean; but if it's any of the cams that come stock in these cars, then yes, especially if you put better 1.25" springs in than stock ones, such as Comp 981 or the equivalent from Crane, Lunati, etc.

 

how?..

larger combustion chamber=higher compression ratio

or larger combustion chamber= lower compression ratio

 

the 2nd one

 

you're taking all that air that the piston sucked in, and squishing it into the combustion chamber.


if theres more space, theres less pressure.. less compression..


lets say your motor sucked in 12ci of air and stuffed it into a 1ci chamber... that would be 12:1...

now lets say it took 12ci of air and stuffed it into a 2ci chamber.. thats 12:2 or when reduced, 6:1


thats also why 305s have such small chambers, but my 400 has a 72cc chamber.

 

thanks...


ok so now what is intake runner volume? what does it effect, ect ?

 

ok so say i go from the stock 58cc to the 72cc of the dart heads..is there an equation to calculate the change.

and how much of a change would be noticable

 

You can get Dart heads in 64, 72 or 76cc.

They also make heads under the old World Products brand name; the World S/R Torquers for 305 are 58cc.

There is no formula to calculte the change, as there are too many other variables. However there are compression calculators all over the Net that you can put your CID, head gasket thickness, piston dish/dome, deck clearance, chamber CCs, etc. into, and calculate your particular combo.

Heads may have a spec for chamber volume, like "58cc", "64cc" or whatever; don't think those numbers are very precise, especially not for stock ones, and most especially not if they've been worked and the valves and/or seats have been replaced. Most heads will actually measure a couple of ccs higher than their spec. The spec is really only good as a general guideline; and is one of the reasons for all the "yes it will, no it won't" arguments you see about why a supposed 11:1 or whatever motor will run on pump gas.

 

i think you phrased wrong... or misleading at least.


yes you can calculate the compression change, but you need to know other variables. if you google a search ( www.google.com ) on compression ratio calculators, you'll find some you can mess with.
another search will yeild the numbers you need for all kinds of stock motors...

 

would these heads fit a 305 ?

Dart Iron Eagle
Specifications:
* Intake runner: 180cc
* Combustion chamber: 64cc
* Intake valve: 2.02 in.
* Exhaust valve: 1.60 in.
* Valve spring diameter: 1.250 in. single springs
* Valve guide diameter: 11/32 in.
* Straight spark plugs

 

no

the intake valve hits the deck of the block.



and before anyone says otherwise, i have the heads and a 305 block sitting in my garage right now... i checked.

 

prob but you will loose compression on a 305 and then you wont feel much of a differance.. basically your 2 choices with a 305 are the s/r tourqersa 58 cc's and edelbrock makes 60 cc heads that you coudl get wawy with on a 305 but thats about it .. unless your goign to custom order heads from afr or pay up the butt to have heads milled.

 

would these fit?..

Dart Iron Eagle

Specifications:
* Intake runner volume: 165cc
* Combustion chamber volume: 72cc
* Straight spark plugs
* Intake valve diameter: 1.94 in.
* Exhaust valve diameter: 1.50 in.
* Valve spring diameter: 1.250 in. single springs

So im between those Dart's, the WP S/R Torquers and the Vortecs.

I rule the vortec's out because it needs a new manifold.

that leaves those Dart's and these World Products S/R Torquer's

Specifications:
* 58cc combustion chamber
* Valve size: 1.940 in. intake, 1.500 in. exhaust
* Rocker arm studs: 3/8 in.
* Valve springs: 1.250 in. single spring, .560 in. max lift
*170cc intake runners



Bottom line money aside. what is the better head for all around performance atop a L69 305 keeping the stock bottom end. stock cam. and stock intake manifold. for an engine with headers and a cat-back and upgrading to 1.6 rocker arms.