combustion chamber shape

Its been many years since I built racing engines for a living. ( 1972 ) The engineering now is amazing and so different.
My thoughts on combustion chamber design may be way off base but here goes.
It seems to me that the combustion chamber shape so popular now is designed for flat top pistons.
Now comes the part where I could be out in left field. With a 1/4 inch pop up on the piston, should the chamber be reshaped to allow better a/f flow?
I have in the last 3 years built 3 motors for the drag strip. a 331 and a 393 small blocks both running low 10's and a 545 just waiting to be mounted. I have a 351 with pop up pistons to build this summer as a lower horse power motor for my daughter to learn to drive with on the strip.
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Larry I think if you massage the domes to fit the chambers they will be fine, I have flat tops in my engine and when it changes I will be putting a smallish dome on them so to get the compression up to where I want it..... these BBF seem to like compression in the 14 to 1 + range..... I can not see where the small block would be any different....



Randy

thanks Randy. My 393 and 545 engines are around 14:1 with the smaller 351 I was concerned about how the higher dome would affect the gasses swirl with a chamber designed for a flat top piston. Is my thinking on this close?

Larry I would massage them and make sure they have a nice smooth contour and run them... I don't think the flame front will affect them as much as the loss in the compression would.... if it was just a street or pump gas deal just do some checking and if thickness is ok just have the domes milled off...... but I would rather have the compression myself...



Randy

What design (canted/inline) is the valve arrangement of the cylinder heads intended for your project, and the material content of the cylinder heads? Also, remember your dynamic friend ........ Quench!

Dave.

the heads I am massaging are sbf performer plus heads

Assuming the the combustion chamber is 60 cc's or so and valve size is within Edelbrock's dimensions, IMO (for what's it's worth) I would NOT attempt to re-invent the combustion chamber on this level of cylinder head. Equalization of combustion chamber volume would be nice although I would look at other areas to do that, unless there is a very minimal amount of volume to equalize, cost vs. volume. IMO, a bit less dome, not that the dome you mention is much, an effort to achieve "quench" and good flame travel could go a long way. I did at one time like smoothing any "edges" of the piston and combustion chambers to help discipline detonation, and more than likely will continue to do so. Although a recent visit to the EVANS RACING ENGINES sponsored Winter Tech Seminar at Terre Haute, IN, while listening to Darin Morgan's presentation, when I wasn't lost in the abundance of information, Darin mentioned (or so I think) an edge or two may offer benefits as to fuel/air distribution within the combustion chamber. I'm not sure this applies to all applications, something to think about!

If I have mis-understood Darin, I will be the first to apologize. I'm glad Darin included great photos as part of his presentation, as I would have surely been lost!

Yes again just mu $0.02 (or less).

Dave.