Ford Repair: Decoding Ford Cylinder Heads, combustion chambers, decade 7
Question-------------------------
Steve, You were very helpful. As a followup, have I given you enough info to tell what engine the heads were designed for? They were represented to me as being 351W heads. I found some info yesterday to suggest they may be LTD II heads, but I have no way of determining what engine they came from. I plan to use them on a 67 Mustang 289-4v. Thanks, Dave.
Followup To
Question -
Steve, I acquired a set of Ford cylinder heads that I haven't been able to decode. Could you help? The casting numbers on the bottom of the heads read: D70E DC and on the inside: 6L24
Thanks, Dave Goff
Answer -
Dave-
As far as I can tell, the heads are for a '77 model Fairlane or Torino. They could have come from another car line, but their original design was for one of those two models. The "D" is the decade code...D=1970. The "7" is the year in that decade...7=1977. The "O" is the model line it was produced for...O=Fairlane & Torino. Finally the "E" is for the parts group that the part will go to...E=engine. As for the second code...it's just a date code. By my best guess the heads were made on December 24th, 1976 for the '77 model year. That one I'm not too positive about, but I feel pretty sure about it. Hope this helps.
Steve
AnswerDave-
Ok...a little more digging has me thinking they're actually 302 heads. What's worse...low compression 302 heads. I traced the number D7OE-DA (too similar to be a different part) to heads used on 302s between 1977-1984 which used 69cc combustion chambers producing a compression ratio of between 8.2:1 and 8.3:1 and producing 139hp in '77. This would have been right in the middle of the oil embargo, so things like cam design would have been weak too, but a 69cc combustion chamber is huge and will hurt performance. By any stretch of the imagination these are not performance heads. Now...in 1967 4V heads used combustion chamber volumes of around 52-55ccs so by using 69cc heads you will lower your compression ratio (which was originally 10.0:1) by at least a full point. If you raise the compression by 1 point you'll see a general increase of 4% in power. Lowering it will have the same effect. That's about as much I can tell from the literature I've got on hand. Hope this helps.
Steve
