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Thread: F-head high altitude head?

  1. #1
    Senior Member 56willys's Avatar
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    F-head high altitude head?

    Okay another random Willys question that came to mind today. I searched the forum and didn't find anything.

    So I know there was a high altitude head for the F134 that had higher compression. How, or is there a way to tell if it is from the outside? Between my two hurricane motors I was wondering if one might have the high altitude. And if there were any markings on the head to tell.

    Thank you, just a geek trying to learn stuff that school doesn't teach!

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    Super Moderator gmwillys's Avatar
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    Great question! I do not know off the top of my head, but will do some research to see. I know on the L heads, a common "upgrade" was to use the head off of a Kaiser Super Sonic head. Our Heep just happens to have one. It's good for a couple more ponies.

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    Super Moderator bmorgil's Avatar
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    It seems I did read somewhere about a "Higher Compression" head for the F134. gm will find it. The way to tell is to measure the combustion chamber volume and compare. The higher compression head will have fewer cc's of volume. You could achieve the same result by "Milling" a stock head to a desired cc volume. Like gm has on his, there was a "Super Sonic" head for the L134. I think it bumped the compression up to 7 to 1 or so.
    Last edited by bmorgil; 04-10-2024 at 08:27 AM.

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    Super Moderator gmwillys's Avatar
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    The only thing I could find was that there were 7.4:1 or 7.8:1 compression heads for the mountains. The casting would have a number cast in it as 7.4 or 74, 7.8 or 78 on the top/passenger side of the head. The stock numbers were 6.48:1 or 6.9:1.

    https://www.oldwillysforum.com/forum...on-head.14947/

    https://forums.g503.com/viewtopic.php?t=72926

    If anyone that may be interested in adding power, here is a snip it of a source I ran across.

    https://www.speed-talk.com/forum/viewtopic.php?t=65959

    I had forgotten about the aluminum heads for the L head from Australlia. The Willywilly head. I threw it in just for kicks.

    http://www.ewillys.com/2022/05/16/wi...heast-ar-1000/
    Last edited by gmwillys; 04-11-2024 at 12:11 AM.

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    Senior Member 56willys's Avatar
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    Thank you for the information! I'll have to check to see if I have one. Maybe if I ever build a hurricane a little more compression would be nice. That second link is interesting, gets the gears turning in my mind! I wonder what a little boost would do to a 134?

    I really appreciate the info! It's cool to learn more about jeeps!

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  7. #7
    Super Moderator bmorgil's Avatar
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    56' I truly enjoy "hopping up" motors. I have been at that since I was 6 years old. Some motors lend themselves well to a hop up. Some do not. A 4 cylinder 134ci flat head motor wont yield much. A slight compression increase probably wouldn't even be felt. It would however be good for the engine. For today's gas, the 134's compression is very low. A bump in compression certainly wouldn't hurt. Just don't expect anything but a little easier starts.

    I like to think of horsepower increases in a percentage perspective. If I add 20% power to a 350 cu in 300 horse motor, I get 60 more horsepower. If I do that to my 134 cu in 60hp Willys, I get a staggering 12 more horsepower. An aggressive cam and intake with a full flowing exhaust will usually get you 10% to 20% of a power increase. The better the engines heads and other design criteria, the better the return. Flat Heads are the worst. To get 20% from a 134 flat head, would take a Lot of work. I would guarantee after you squeezed 20% out of it it would be a fussy, hard to start and rough idling little thing. If I had a high compression head lying around, I would use it for sure. Why not! But I certainly wouldn't spend any money on "hopping up" a L134. I am sure someone has though! To get more horsepower you increase the RPM potential of the engine. Everything about the 134 says keep the RPM's low.
    Last edited by bmorgil; 04-11-2024 at 06:55 AM.

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    Super Moderator gmwillys's Avatar
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    Bmorgil would know better than anyone when it comes to hopping up engines. His daily runner pickup sounds amazing with a great throaty note.

    As with the links provided in my previous posts, there has been a lot of effort put into increasing the performance of the 134, but most just put the effort into just making the engine reliable and smooth running. Those aspects are worth a whole lot more than any performance gain you may ever get.

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    Senior Member 56willys's Avatar
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    I think reliability would take a major hit. And for probably not much gain. Although experimenting would be a fun project. But Flossy will stay stock and reliable. But in the future if I build another jeep I might consider something crazy (and probably stupid) Being that all my family members who are into cars and all my buddy's are all into mustangs, V8s and other fast stuff. I'm the only one who just sits back and has a low horsepower cruiser. So it's really easy for me to get crazy ideas about keeping up with the horsepower!

    As always I really appreciate you guys giving me information. The main thing I can see about having higher compression would be for today's higher octane fuel. I believe back in the day they only had 70 or so octane? So the little compression gain might be worth it today.

  10. #10
    Super Moderator bmorgil's Avatar
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    56', I promise you I have seen more boy's passed on the track that didn't understand the basics, than I have seen those that did understand get passed. When you start where you are starting, things make a lot more sense when you jump into the advanced stuff. So many today want the answer not the process. You can rest assured the day will come when those who rush in with money and incompetence, watch from behind those who understand how the whole thing works from the very basics, finish in style. When you build your first Hot Rod, it will be a winner. Flossy is showing you how it all started.

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