[Old Goat Racer]

Does anyone know what the flow numbers are on a round port 72 cc E-head outta the box. Is 87 cc any different.

[Skip Fix]

Edelbrock has them on their site. I believe they have the 87c listed as slightly lower due to the deeper chamber and different short turn radius. Not a lot of difference.

[steve25]

The 72 cc ones I have tested flow 278 to 284 intake cfm @28”.

The 87 cc ones are some 5 to 8 cfm less due to the shrouding of the chamber, this also means that ultimately the 87 cc ones can not match the max ported flow numbers of the 72 cc heads, but you can get darn close if you step up to a 2.19” valve.

And yes you can find the numbers for both on the Edelbrock site.

[Steve C.]

Edelbrock flow umbers on page 118

https://edelbrock-files-v1.s3-us-wes...ck-Catalog.pdf

As Skip mentions the difference in flow numbers is due to the chamber depth.


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[Steve C.]

"Like the original Performer RPM casting with its scalloped chamber, the Performer RPM CNC is available in two volumes: 72 and 87 cc. While the same basic casting is used for both applications, the larger combustion chamber is achieved by machining it some 0.120-inch deeper into the deck surface, and that places the intake and exhaust valve seats higher in relation to the port floor, which subsequently negatively affects airflow by some 10 to 15 cfm each."

Source: https://www.motortrend.com/articles/...ead-edelbrock/


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[Old Goat Racer]

Great info. Thanks for doing my homework.
OGR

[Skip Fix]

For the increased flow of the 72 Dave Bisshop at SD liked them and a dish to get what CR you need for pump gas.