81A heads?

[scooder]

Originally Posted by 47 flatbed

In the short these heads will not improve compression any more than the stockers on the engine now?

Yes, the 81A head is lower compression ratio than stock 59AB head. Swapping yours would lower your compression and take away a bit of torque.
So don't do it.
They do breath a bit better, but on a stock engine breathing in the head area is not a performance changer. If you read JWL's book, even very small chamber heads didn't hold back breathing, they raised power nicely.
Martin.

[Kube]

Originally Posted by Bruce Lancaster

81AS is listed in the bulletins as 60 CC, I think the highest compression head Ford cataloged.
S means I think that it was strictly over the counter, not used in production. Probably S stands for "service" or "special."
The only cataloging I have found says somethink like "natural gas and high altitude"
It was apparently discontinued before WWII and so was hard to find when stock car types discovered it. Ron has a baxkground in the Danbury flathead racing, I bet he has some of those!
Canadian bulletins rated all the heads for both 221 and 239, listing it as producing 8 to 1 on a 239 motor.
There were also a couple of bigger CC S heads designated for 239 use originally.

"S" = special in Ford's system.
I have a set of NOS 99AS heads that I had recently installed upon a '40 Merc engine destined for my '40 Ford convertible restoration. This particular Ford is a documented Police car, factory equipped with the Merc engine and high compression heads.
The documentation requests the heads and all other accessories be factory installed. Whether or not that happened or the dealer installed them, I can't say...
If I recall correctly they were 65cc's, the "low end" of the specified volume.

[Bruce Lancaster]

The "Special" heads, usually called Denver heads:

81AS 60-62 CC 8-1
99AS 65-67 CC 7.6-1
19AS 70-72 CC 7.1-1

CC specs and compression ratio computations are from a Canadian service bulletin that covers more heads, both Canadian and USA Ford, than any other I've seen. The ratios above are for 239 engines...they listed a ratio for both 221 and 239 on all the 24 stud heads.

[Bluebell]

So, for my own clarity if I was to put together a c59 or c69 block with a std cam, would 81A heads (or C7RA heads) need machining to clear the valves?

[Brian]

The 81A heads will need attention as they were designed for the early 24 stud engines which had valves closer to cylinders...the C7RA heads are original equipment on 69A's so are a direct bolt on...disclaimer after checking for valve and piston interference.

[Bluebell]

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Thank you Brian.

[topfuel724]

My C7RA6050-B heads are aluminum "Made in Canada" heads. Are these the same as the "Denver" high compression or high altitude heads?

[scooder]

No I think the proper "Denver" head was 8:1 yours are about 7.5:1 if I recall correctly.
Martin

[Bruce Lancaster]

Denver is in the USA. The C7RA-B heads are from Canada, and since they are the only Canadian head that was widely sold in this country (both as original and as Weiand made "cheater") they are widely referred to in USA as just "Canadian Heads"...few US rodders have ever encountered any other of the many Canadian heads.
The Denvers, so-called because catalog referred to high altitude application, are all iron.

[Ralph Moore]

So a pair of 59AB heads on an earlier engine(38-41) would pep it up a bit.
I have such a motor with no heads, and an extra pair of 59 heads.

[Brian]

Ralph, I doubt you'd see any difference in performance by putting 59AB heads on an early engine.

[scooder]

Ralph,
In theory, yes it would. Wether you'd notice the difference, I can't say cus I ain't done it. It's definitely a step in the right direction.
Higher compression ratio = more torque, better throttle response and better mpg.
I believe you should feel the difference, it won't be a big difference, but a difference no less, it should feel just a bit sweeter.
This would be noticeable if you drove it with the early heads and them swapped on the 59AB heads and drove it again. Ideally with a tickle less advance in the distributor.
Martin.

[southfork]

Are Denver heads sometimes referred to as "Rocky Mountain heads?" Someone was mentioning the latter to me as being the best ones.

Also, where do Ford EAB heads stack up compression-wise?

[38 coupe]

EAB heads are the highest compression ratio factory heads that are commonly available. They are a very good choice for 8BA style engines.

[Henry/Kokomo]

Anyone have any experience with EAB heads on a 59ab engine? Other than the water hole that needs to be plugged, is there any reason that wouldn't work? Should raise the CR, I would think, Thoughts?

[scooder]

EAB head is 71 cc and 59AB head is 76 cc, so your compression ratio will go up.
I always measure to make sure of chamber size, it does vary from Ford spec sometimes. For instance the 8BA is ment to be 76 cc, all the uncut ones I've measured had 80 cc +- 1cc.
Martin.

[Ol' Ron]

One thing I discovered when writing my book I checked dozens of heads and they were all over the map. One head had 115cc, can't remember which one it was. So just assuming a head has the right cc, is not a good move. MEASURE.