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Technical 354 Hemi power potential

Discussion in 'The Hokey Ass Message Board' started by tartar_sammich, Jul 12, 2015.

  1. We have a 354 Hemi in a '37 Ford we are going to rebuild. It was built as a drag engine in the 60's and has a Crane roller cam, Mech. Hilborn fuel injection, 11:1 Forged true pistons, and some other goodies. We would like to keep the compression ratio. I have heard Hemis can run a higher C/R with pump gas than a wedge head can. Is this true? We have no idea what the cam specs are. We would like to see 400-450 horsepower naturally aspirated. If we can get the fuel injection converted to EFI at a reasonable price we will, if not it'll be carbureted, probably a 750 Holley. We're going to convert to a distributor with electronic ignition as well. Can we get those numbers out of it?
     
  2. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    Yes. And if you do decide to not use the Hilborn, let me have first shot at it.
     
    kidcampbell71 likes this.
  3. It'll be a little while before we start on it, frame work comes first. I'll let you know then what we decide to do with it.
     
  4. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,657

    Rusty O'Toole
    Member

    Chrysler got 355 HP out of a STOCK 1955 Chrysler 300 354 so 400 should not be too much of a stretch.

    Developed HP means very little if it comes at too high RPM. For street use you are better off with a fat torque curve and slightly lower max HP.

    Chrysler ads used to brag about "mechanical octanes" meaning their engines developed more HP than rivals of the same size, even though they had lower compression and burned regular gas.

    They don't lend themselves to high compression as well as conventional wedge head engines, one reason Chrysler switched in 1959.

    9.5:1 is about the limit for pump gas on the street.
     
    stillrunners likes this.

  5. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    ...well, I'll disagree with 'ol Rusty........

    We have not sent a rebuilt EarlyHemi out the door with less than 10:1 c/r in over 20 years. No complaints, even from some of the real 'grammas' we worked for.
    The Hemi combustion chamber allows for about 1 full point higher c/r than a similar equipped wedge.

    Now, 11:1 on the street might be problematic until you have the ignition and intake dialed in, and you might need some octane booster. Additionally, much depends on the cam profile; how much valve overlap?
    You are on the edge.

    As for efi, talk with Fran at http://foxinjection.com/index.html Cheap? Hell NO, top shelf? hell yeah.

    .
     
  6. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    NO, MaMopar made the switch because the corporation was getting too many damned bean counters in high level positions and out voting the engineers.

    .
     
    deucemac likes this.
  7. We are not sure of the specs on the cam. All we know is it's Crane solid roller. When we get it out we will call them and see what they say. If it's too radical for street use we will get another one made. If we are to get one made I would expect it to be in the .550 lift range or higher with 250 something duration, probably hydraulic roller.
     
    Karl Fields likes this.
  8. They don't lend themselves to high compression ..,,

    Boy do they like to get some boost from a 671. Put about mild 8 psi on to the static 8.x:1 and your about 12.5:1. They like that plenty :D go figure.




     
  9. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    ...better start reading every post regarding EarlyHemi cams....... Using lifts above .500 costs lots-o-money.
    You can start with this one:
    http://www.jalopyjournal.com/forum/...s-need-valvespring-help.981058/#post-11054622

    .
     
  10. We should rate early hemis like Rolls Royce rates their engines, when someone asks about HP the answer should always be "Sufficient"
     
    Kan Kustom, 73RR and Remcolent like this.
  11. Watered down is too much lift and you can't get springs that work without binding so your option is to get springs that are too tall for the valve train. you can get adjusted valve train components but that is not going to be cheap.

    Or you could read through it several times and develop questions to ask and consider it research.

    I lean toward old grinds because I have not fully embraced the new millennium. The new millennium is all about lift the old idea was lots of duration, and less lift. I am probably way off base in my thinking but in my mind you open the valves farther to let more fuel and air in, or you can leave them open a little longer and accomplish the same thing.

    You may open that bigger up and discover that the cam you got will work just fine. Then you'll just be a pair of 4 bbls and good ignition away from happy motoring.
     
    Fast Elvis likes this.
  12. Gotcha. Hoping that cam will work. ImageUploadedByH.A.M.B.1436809467.936743.jpg
    Here's a pic of the springs on it now. Probably does no good to see one but everybody likes pictures.
     
    kiwijeff, 69fury and Krash Vegas like this.
  13. tricky steve
    Joined: Aug 4, 2008
    Posts: 449

    tricky steve
    Member
    from fenton,mo.

    Bob walker of Hot heads fame, prefers the 354, over the 392.. he built one for engine master challenge and did really well with it..
    To answer your question, you can make as much power as you can afford.
     
  14. Actually, Hemi combustion chambers *like* high compression. But their valve train complexity made them way more expen$ive than comparable wedge heads.

    As 73RR pointed out, the bean counters won out over the engineers.
     
  15. Relic Stew
    Joined: Apr 17, 2005
    Posts: 1,208

    Relic Stew
    Member
    from Wisconsin

    The hemi not good for compression thing;
    A large chamber dome needs a large, heavy, piston pop-up to get compression. Now the chamber shape is rather spread out, with slow flame travel, and loses a lot of heat into the piston and head surface. A compact head chamber with a matching piston dish will get the same volume with much less surface area, promoting faster flame with less heat loss.

    The hemi is good for air flow. A flat top or small pop-up with with some boost is the hot ticket.
    13.jpg
     
  16. Unfortunately a blower is out of the question. Too big to fit under the hood and we don't want to cut it. Also $$$
     
  17. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    Jimmy2car
    Member
    from No. Cal

    I watched a 354 based Hemi on the Dyno at Vintage Hot Rods in Chico, CA. The engine was built by Dan Miller (rip) and Gene Evans and tuned by John Beck of Pro Machine.
    It was at least sponsored partly by Hot Heads and was built for the EMC . I think it came in third.
    It made 645 HP . Very, Very impressive
     
  18. hh came in second place. i run a 354 with a cut down 392 crank. being .060 over makes 392 cubes in a smaller lighter package with better port angles. these early hemis make enough power that a newer hot rodder will piss right down his leg the first time or two out. 450 hp is a very easy thing to do. scrap those alum retainers.
     
    Remcolent likes this.
  19. Good to hear. Not questioning you but what's wrong with aluminum retainers? Just wondering because I don't really know the difference
     
  20. when you drop a valve it will become very apparrent. steel or titanium is a much safer bet.
     
    FinnishFireball likes this.
  21. bostonhemi
    Joined: Dec 1, 2011
    Posts: 695

    bostonhemi
    ALLIANCE MEMBER

    Those rocker arms looks adjustable or am I seeing things?
     
  22. Yes they are but it is only a bolt and no jam nut... kind of weird
     
    Last edited: Jul 14, 2015
  23. bostonhemi
    Joined: Dec 1, 2011
    Posts: 695

    bostonhemi
    ALLIANCE MEMBER

    Looks like a great project. I had a 331 built 60 over with a mystery cam might be 510 at the spring. I hope to have it done this summer then off to the dyno and will post results when I can.
     
  24. Do you know how much a dyno session costs? I'm curious because it is something we would like to do. I'm sure it varies in different areas but we're just trying to get a ballpark estimate
     
  25. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    Without closer inspection I'd say they were Gotha (brand). OK for the time but not so much today. We can convert them to 'normal' screw/lock.
    Since you are admittedly new to EarlyHemi engines I'll not complicate the conversation about combustion chamber design, just suffice to say the Hemi has the best design ever made....and now the wedge heads will jump in....

    Suggest that you get the cam details as first order of business.

    .
     
  26. PontiacPower67
    Joined: Mar 24, 2015
    Posts: 43

    PontiacPower67

    Let's see some pics ... Sounds like you got a good thing going so far ... Start you build thread.
    I'm sure everybody would like to see...
    God speed
     
  27. LOL that's all adjustable rockers are is a bolt and jam nut. Some don't even have a jam nut.

    These are McGurk's

    [​IMG]

    [​IMG]

    You would be wise to loose the aluminum retainers as has been mentioned before. I have run them and had them crack on me under a megaload ( high RPMs) got lucky when it shit on itself I shut her down and all that happened was I needed to change the retainers that were cracked. That engine ended up with titanium but steel will work well for most street engines. I doubt that your hemi is going to spin that high anyway.
     
  28. ImageUploadedByH.A.M.B.1436894579.052331.jpg
    ImageUploadedByH.A.M.B.1436894653.620646.jpg ImageUploadedByH.A.M.B.1436894677.866298.jpg ImageUploadedByH.A.M.B.1436894703.746162.jpg ImageUploadedByH.A.M.B.1436894764.556922.jpg
     
    stillrunners and kiwijeff like this.
  29. Ah ok. I've just never seen adjustable rockers with just a bolt but then again, I'm 17 haha. Do they stay in adjustment as well as other adjustable rockers? It may not be the easiest thing to adjust the rockers on the car because it's such a tight fit, but I guess time will tell on that one.
     

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