I have seen where some have criticised the D2 heads as being pretty bad - but I cannot seem to find a consensus on why they are bad, or why they are not wanted.
I am looking for a spare set of heads to have "just in case" there is a need to replace the D3 heads I have now. This is a truck application, with an RV cam, and a balance between mileage and power.
Please comment, and thanks in advance.

 

Briefly:

The D2VE heads are a one year only attempt by Ford to cut compression & reduce emissions by designing a totally diffenent "open" combustion chamber. Unfortunately there is very little area to provide quench, and these heads are more prone to detonation. The D3VE heads that replaced them return to the C8, C9, & D0VE head style of chamber, but "raise" it farther into the head, in the process enlarging it to roughly 92-95 cc's. There are some differences in the D3 exhaust port due to this, but these heads can still be made to work very effectively on a street engine and moderate race applications, especially so when setting the correct deck height, maximizing quench, and choosing the best compression/cam/ignition curve combination.

It is generally thought that the D2VE heads are not suitable for much of anything. They will work reasonably well if the compression is very low (possibly 8:1 or less), which is the wrong solution for power or MPG.

D3VE heads are so cheap and readily available that there's not much reason to choose the D2 heads unless it was an emergency.

You might consider going to www.reincarnation-automotive.com & joining his site; it is relatively cheap and has a much better explanation, including pictures of the heads. The owner posts here occasionally under the name "The Mad Porter".

 

Thank you, Homespun, for that very effective answer.
Similar things happened in the FE world in '65/'66, and later in '72, so I know exactly whereof you speak.
C4 Fe heads are more desirable than most other early heads due to larger valves, C8AE are very good, C80E are among the most desireable - and rare, just like the D0O heads - same principle here.
Again, thank you.

 

You're most welcome.

Gratuities are welcome, too. I accept Cammer parts.

Are C8OE the police interceptor heads in the FE world? I am not an FE expert and have forgotten 1/2 of what I learned in the first place.

 

One good thing Ford did was to be relatively consistent with casting numbers and designations.
The O designation is the same in the FE series as the 385: CJ!
I'm not a racer or a power monster, I just like things to run right and reliably.

 

I have a rebuildable truck 390 (mirror 105 casting, not the FT engine) with D2T heads for sale, a good running 360 2V for sale, and a worn out 352 with C8AE heads.
I am switching to a 460.

 

The reason the D2VE heads are so bad is that the chamber is very large and open for its cc size. They are just like the open cleveland chambers only worse because the bore is so large. There is absolutely no quench pad and this makes for a lazy flame front propogation rate and more distance for the flame front to travel before imparting pressure on the piston crown. This requires more timing for best power and there in lies the problem.

The additional timing coupled with lack of quench spells detonation with any cranking compression or high C/R.

When you add a cam with more duration and overlap like most performance cams possess you have such a lazy flame front that the things wont idle with out 25 degrees of initial timing. I know whereby I speak believe me !!!

I throw them in an iron recycling bin.

Regards,
Scott J. / RHP
http://reincarnation-automotive.com
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Scott: Thank you for your well presented information. I like the looks of your site, and the "evolutionary" explanation of your work is well reasoned as opposed to being merely opinionated.
I hesitated to join it, even though it is very good, simply because my focus is on cost and reliability for my '66 F-100 rather than performance. Thanks again for the details, it is exactly the kind of information I need.
By the way, I lived for many years on North 7th, between Mullen and Orchard. There was at one time a tire shop on the corner of Stevens and 6th, but it has been many years since I was there.