390 heads performance questions.

I have a pair of C8AE 390 heads casting # is 8090R and the date codes are 6H11 and 6O20.
Does anyone have any info on how good they are performance wise? And, will polishing them increase their utility greatly?
Are they a good or average head in general?

The intake ports are gigantic! The exhaust ports are about 3/4 the size of the intake.

The valves to fit them are Clevite #211-1836 --- 25-1539 for the intake, (gigantic valves) and #211-1939 --- 26-9014 for the exhaust, (rather tiny if you ask me).

So what's the what with these heads you pro-builders you?
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according to the Ford parts interchange manual, they are 1968 castings for 360/390/428 with thermactor emissions. Chamber size is 67-70 cc, valve sizes are 2.02/1.55, 2.34"x1.34" intake port, 1.84"x1.34" exhaust port.

There are several different variations of the C8AE, there is a C8AE-A, B, H, F, J, and N. The A, B, H, and F are all practically the same. The J and N are 427 "low riser" castings, they spec out as follows: 73-76 cc chambers, 2.08/1.65 valves, same size ports as the others.

<font size=-1>[ This Message was edited by: indigo66 on 11/5/04 7:31am ]</font>

Thanks Indigo!

You're the bestest![img]/phpBB/images/smiles/icon_tup.gif[/img]
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C8AE-H is probably what you have. They are high-port emissions design, which is not bad, but they run out of breath around 5000 rpm as delivered.

I run a pair on my 427, and ironically, the intake port location is the same as med riser, but the short side turn is a lot uglier. What I did was port the living heck out of them on the top side of the port, clean up the short turn, and add 2.15 / 1.67 undercut stem valves and opened the bowl to match.

They run great. In addition we bore matched them to the 427, however, it wouldnt me needed on a 390, they should be there already

For a cheaper job, I'd clean up the bowls and the short side, open the exhaust all I could, and put CJ valves without new seats. I'd gamble on 40 hp more above 5000 with the right cam and a good set of headers after the work

Thanks for your input! I thing I will do something like that with these...
The casting #'s on my 66 heads are... C6-AE-R and are cast dated 6A7 and 6A8.
Are these any good?
I could use either set but these mentioned here are in excellent condition and don't have any bad exhaust bolt ears or any deformitys that I've seen...

Gary
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The C6AE-R's arent mentioned in indigo66's post...
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C6AE-R is a different story and technically a "better" head. Its also known as a "poor mans CJ" The intake and exhaust ports are a bit better and the chamber is shaped like a CJ, however they are also larger chambers.

If you are building a motor for a certain chamber size and buying pistons for a specific ratio, I'd use the C6AE-R

However, if you are just swapping heads, a good set of C8AE-H will rase compression by a point, probably have a smidge better quench by design and will make gobs of low-end and mid range with their high port design

Bottom line, high RPM C6AE-R gets a slight nod if you have the compression, low RPM C8AE-H work real well stock, and pretty slick with some mods