Zoom!

Heads are about the single most important determinate of your engine's output, right?  So you'd better pick the right starting point to build your engine.

Without getting into real exotic choices, 385 series head choices are limited to D0VE passenger car castings, the D0OE CJ castings if you can find them, SVO aluminum "CJ" castings, and the new aluminum Edelbrock heads.  Any of these heads can be used "out of the box" or ported to increase flow.

All these numbers were reported at a standard 28", but are from different sources, making comparisons a little chancy.  If you want the excel file click here.  Sources for the data are as follows.

The ported D0OE data is from Mike R for his extensively ported heads.

"On the exhaust side I smoothed the bowls below the valve, removed the emissions hump completely, reshaped the valve guides to a cone but left a point on the guide to direct the flow and raised the roof and widened the port quite a bit as well a smoothing the short turn radius."

"On the intake side I smoothed the bowl, straightened the port entrance where the head bolts humps are, and reduced the large rectangular chunk of metal behind the valve guide as well as reshaping the valve guide to some degree. I also worked on the combustion chambers and got a three angle valve job."

"I think my 211 [exhaust flow] is just about maxed out without adding some type of port plates or welding the ports."

The ported SVO aluminum CJ data is from http://www.kendrick-auto.com.  If is very similar to data from "BigD" for his heads.  The unported SVO aluminum CJ data was reported in the June '99 Car Craft and provided by "gregaust."

The unported Edelbrock data and "stock" data were reported in the May '01 Car Craft. It didn't report which of several different "stock" castings they were using, but they did report the Edelbrock numbers were independently measured by the engine builder.

The ported Blue Thunder (Ford exhaust port) data is from (name withheld) who reported the exhaust flow was near to maxed out, but the intake would probably make 400 CFM with more work.

The data supports several conclusions consistent with traditional wisdom.

1. Although the intake flow of stock heads is reasonably good, the exhaust flow sucks - a lot.
2. Ported SVO aluminum CJ intake flow (red on the chart above) and ported D0OE CJ flows (orange on the chart above) are about the same.  This shouldn't be a surprise since the ports are almost identical as cast.  (I attribute the difference in ported flow numbers in the data to the different porting jobs done on the heads, not the potential of the casting.)
3. Ported SVO aluminum CJ exhaust flow (dotted red) is almost 25% better than "extensively" ported D0OE CJ port flow (dotted orange).
4. Porting SVO aluminum CJ heads made an enormous difference in their flow: intake flow goes up over 20% but exhaust flow goes up around 50%!

The interesting thing about this data is just how good the Edelbrock heads are.  We'll have to wait for at least one more independent, confirming flow test, but if these numbers are correct the unported Edelbrock heads are the equal or better of the best ported D0VE and D0OE heads.

If you've got any flow data for 385-series heads please let me know.  I'm interested in data that confirms or contradicts anything I've got.  I'd especially like to see flow data for 

• ported D0VE heads,
• the effect of port plates in the exhaust ports for iron heads
• ported Edelbrock heads to confirm my numbers.

Send me what you've got and I'll update the page and give you credit as the source of the data.

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