Do any of you know if they exist and what their chamber size is? i saw a pair on ebay....it said they were D3VE-A2A's and the picture showed they were closed chamber, they also appeared to have the pedistal mounting for the rockers (i think thats the right term at least....non-adjustable\not stud mount?). could these heads be a direct bolt on for my existing open chamber d3ve's using my existing rockers, in order to bump up my compression as a set of D0VE's would do? any help would be much appreciated. thanks in advance.

 

To answer your question,yes those heads do exist.I have a pair that came off a 73 460 out of an LTD.They should be a direct replacement for your open chamber heads.I am not sure of the chamber volume as I have not cc'd my heads yet.They do look like they would raise compression or at least induce quench.

 

D3 means they were cast in 1973 and all '73 heads other than PIs were low compression 91.4cc chambers for 8.5:1 c/r when compared to DOVE 75.8cc chambers and 10.5:1 c/r.

They won't increase your current c/r or improve performance. If that's what you're after, you need to go to to a '68-71 head or change piston height.

If you do decide to use them, grind off the smog bump in the exhaust chamber. It was cast there to reduce emissions by distorting exhaust airflow for a longer burn and elimination is worth 20-25hp.

 

George: are you sure about that? i could SWEAR that just judging from the picture, the chamber size wasnt far off from the previous generation heads. in fact, the chamber looks to be the exact same shape...i was just wondering if anyone out there knew specifics about them like CC's, and also, where the heck they came from? i wasnt aware of any high compression big blocks 73 and up. were they made for engines with lower compression pistons or something? thanks for the input guys.

 

You have a pretty good eye if you can spot a difference of 16cc in a picture of a combustion chamber.......

Ford, like most manufacturers, went to low compression engines in 1972. With the exception of PI heads through '75, '71 was the end of high performance and higher compression 385 series production engines. You can still purchase 4-bolt main blocks and CJ style aluminum heads through SVO.

If you're building a performance engine, it doesn't make any difference if you use the '72-78 heads as c/r can be determined by piston height.

 

the chamber sizes by just looking them look the same, but look at the pistons from the different years. the earlier engines had flat top pistons with 2 valve refiefs and if you look at the '73's for instants you will notice a dished piston about 19cc to about 22cc in this area that lowers the compresion. you said that you had open chamber heads on your motor that were D3VE'S that's impossible. D2VE-A2A or AA is the (( ONLY )) year cast with open chambers for 1972. i guess you typed in an error.

 

If you're not familiar with casting numbers, a good rule of thumb about determining the difference between early small chambered 385 series heads {'68-71) and later ('72 up) larger chambered emissions heads is to look for the smog bump in the exhaust chamber. If it has the bump (called thermo something), it's a '72 up head.

I have a set of D20E AB PI heads that came with 2.197" intake valves, 1.653 exhaust valves, stud mounted rocker arms and hardened pushrod guide plates. They had the smog bump when I bought them.

And, all '68-71 heads had stud mounted rocker arms. '72 up, other than '72-74 PI heads, had pedestal mounted rocker arms.

The ONLY big valved, big chambered, cast iron heads with hardened pushrod guide plates referred to as CJ/SCJ are casting number DOOE, sold in late '69 through 1971. From '68-71, PI and CJ heads were the same head.

At one time or another, I think I've seen every '68-71 head, including Lincoln casting numbers, referred to as a CJ head. So buyer beware.

 

George and cobra, thanks for the information. i was a little mixed up on a few things and you guys told me exactly what i was looking for.

 

Georgedavilla,
You said that CJ/SCJ D0OE heads are big valved and big chambered. I always thought they were small cahmbered. Somewhere in the neighborhood of 72 cc's???

I think the major confusion in this topic is coming from the misconception that the D3 heads on the orginal poster's truck were open chambered, which is incorrect. They have large combustion chambers 92-93 cc's but they are in fact closed chambered, i.e. shaped like a "D". As stated previously the only "open" chambered heads are the '72 models. Many people confuse "open chambered" with a "large combustion chamber" when they are not the same.

 

My descriptive error. The DOOE combustion chambers, at 73.5cc, are the smallest of the 385 series. My reference is to the DOOE intake and exhaust chambers, which are far larger than standard production heads and for that reason require different intake and exhaust gaskets than standard production heads.

 

Where are these casting # anyway??? I odered a book om big blocks,but its not here yet

 

The casting numbers for heads are on the exhaust flange, just outside of the tappet covers.

JJ

 

[updated:LAST EDITED ON 24-Nov-02 AT 07:29 PM (EST)]

Open or closed chamber has nothing to do with a "D-shape," nor the size of the chamber. The D3VE-2A2 (etc) is an OPEN-chamber. An open chamber is one that has no significant quench (squish) area on the sparkplug side of the chamber (even if it is a "quench-style" chamber on the intake side). The early 289 (255 and 260 also) SB heads (54cc and smaller) are true closed-chamber heads. Take a look at both chamber shapes (relative to actual cylinder bore) and it's quite easy to see the difference. Easier to "see" than to explain.
Open-chamber heads suffer less intake valve shrouding than the closed-chamber designs, as a general rule. A plus for torque and lower RPM, lower valve lift output. You can reshape the closed-chamber around the area in question (my preference), but that's a tedious project (imho). Just debur the open-style chambers to remove rough stuff (potential hot spots in the casting) and have them milled to suit your compression desires (.020-.030" is usually good for a pump gas streeter, any more than that and valvetrain geometry gets FUBAR'd and/or compression gets too high for a heavier vehicle on standard gas). Detonation sucks.
D3VE-2A2 is a '73 revision Lincoln 460 head. I forget if that's been mentioned here. Sorry if I'm being redundant <doh!>.
Hope it helps - somebody, somewhere.

JavaRocket