Old vs New Edelbrock Heads
 

With regards to round port e-heads, does anyone have any race track or dyno data on the difference between the older style combustion chambers and the new fast burn style? Is it worth to have them converted to the new style?

Heart Shape Combustion Chamber Dyno Test

https://www.sdperformance.com/newsStory.php?newsID=41

https://www.sdperformance.com/newsStory.php?newsID=38


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Chamber Chatter
No testing data here, but some might have interest in the Edelbrock development of their heart-shaped combustion chamber for the Pontiac cylinder head.

https://www.motortrend.com/how-to/in...ead-edelbrock/


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Each chamber has its place.... You can go far wrong with the CNC chamber. In our few "back to back" tests we haven't noticed much difference other than tuning requirements.

In theory motors with high piston speed should benefit from a fast burn chambers, and of course high reving motors like above 6500.

i think for boost the old style is better....when i had mine opened up from dave at sdperf i asked for the heart shape chambers but since i had told him it was for a blower motor he advised against the faat burn chambers

How so?

The CNC chamber is more sensitive to cam timing, piston design and burn rate.... But it's a good chamber and glad we have a choice.

Who does the conversion of older chambers to the newer hear shaped? I asked SD (before the fire) about doing that to a set of my 72cc E heads and he said they dont offer the service anymore since edelbrock sells them that way now.

Is it not also an issue with the new HSC if you want higher flow numbers,(cfm's) you need the old Edelbrock heads?

Flow wise the CNC chambers have an advantage.

We designed a program around 2000. It was originally created for one of Butler's "Engine Master" entries. Unfortunately with today's labor costs and inflated parts prices it wouldn't be cost prohibitive to convert a set.

Thanks Paul. You got me thinking. I wonder what kind of timing the old chamber E- heads use. I thought the old chambers were using around 36-38* timing.

With our 505 we were at 34* on the dyno. 91 octane. We ran C12 at the start to find our best timing.

My old bathtub Eddy chambers work best at 39 degrees timing for best mph.

My two "old" chambers one likes 38 the other 40.

Thanks for all the replies, it sounds like there is no reason to bother with changing anything. If I was class racing and chasing every last pony then I would say it would be worth it. For my mild bracket motor not worth it.

How much power or et do u lose with say 35 degrees?

Hi Darby: What heads are you running now? Or are you still running the KRE D-ports? Thanks

Not a lot maybe 4-5hp.

Yea, So not even worth running it that high then really if no major gains