308 block Max HP and displacement

50C8DAN
50C8DAN Senior Contributor
in HUDSON
What has been the highest HP and displacement ever gotten from a 308 block?  I have heard some pretty big numbers like 37X cu in, or something like that but I am not convinced this is doable.

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  • 50C8DAN
    50C8DAN Senior Contributor
    Over on HAMB someone in the Indianapolis area that goes by Paceracer50 and is a Hudson guy posted this, 386 and 421 cu in. Not sure it ever happened:




    Yes the High Nickel Hudson blocks all the way through 1956 was one tough old block to do any machining on. New tools can take it without much problem but die grinder tools have a severely limited life span.
    On the four holes shown in photos 6 & 7 these are not subjected to oil pressure as the cam bearings do block these holes. I filled mine up with the black Mopar ATF-RTV then installed the cam bearings. Just trying to keep the outside of the block clean as they were weeping a little oil after a hi-boost run.

    pdq67... I am taking a Hudson 308 out to 386 cubic inches and plan on going to 421 on my next one. I really like those old Packards but I'm sticking with the King of the Flatheads... Hudson!

    thanks and more will be coming soon. Business at the shop restoring a 1950 Hudson PaceMaker convert with a 54 Hornet 308 2bbl engine is taking presidence.  
    PaceRacer50
  • dwardo99
    dwardo99 Expert Adviser
    I have one sitting in my garage that is 386 cubic inches. Well, maybe it's 385. 
  • BillUSN1
    BillUSN1 Member
    dwardo99 said:
    I have one sitting in my garage that is 386 cubic inches. Well, maybe it's 385. 

    Details?

    Cost to build?

    Fuel required?

  • Frankvintagefullflowcom
    Frankvintagefullflowcom Senior Contributor

    dwardo,

    Mind if I ask the bore & stroke of that 386 so I can "do the math" for myself? I think that 421 will be made by IHC.....the Imaginary Hornet Co.

    F

  • dwardo99
    dwardo99 Expert Adviser
    To the best of my recollection it is 3 15/16 x 5 3/16, which makes it 385 by my quick calculation. It is something I acquired from my uncle's estate. He had it built is the mid 60s by Jack Clifford. Cost to build? Astronomical, but unknown. It basically has everything in the Clifford catalogue, 7x valves, Isky cam, 1/2" studs, Clifford head, balanced, etc. etc. etc. I am sure it has a 7x block relief and other machine work. He was racing a Hornet-powered Jet at the time and wanted to step up his game so he ordered that one built and he must have just opened up his check book. Then he got interested in airplanes and never even ran it. I don't know what fuel it requires because I don't know the compression but he always insisted it would be usable on the street. He always did drive his Jet on the street as well as race it so I guess he specified that but I don't know for sure. When he passed were looking around for a suitable car to put it in and I wish we had. 
  • Frankvintagefullflowcom
    Frankvintagefullflowcom Senior Contributor

    Interesting...... 

    F

  • dwardo99
    dwardo99 Expert Adviser
    A thought just occurred to me. Knowing my uncle, he might have planned to run that engine on Propane, which has a rather high octane rating. At that time, my father was like the cartoon character Hank Hill, he "sold propane and propane accessories". Most everything my father and uncle drove ran on Propane, usually as a dual-fuel setup. I am ignorant of what the class racing rules would have said about that, and I know for sure his Jet did not run on Propane, but I wouldn't put it past him. 
  • dwardo99
    dwardo99 Expert Adviser
    Yeah, I knew about the valve thing. I think industrial engines that used Propane back in the day used hardened valve seats. I'm not sure how big a deal it was. All of my father's company cars ran on it exclusively and he drove them 100,000s of miles and I never remember an engine problem (except the VW microbus). Anyway, it sounds like something Unk would think of. I think he may have had the only Twin-H Hornet ever to run on Propane. 
  • 50C8DAN
    50C8DAN Senior Contributor
    OK we pretty much have run the limit of displacement so how about any HP or Torque numbers?  
  • dwardo99
    dwardo99 Expert Adviser
    I would not even care to guess. 
  • dwardo99
    dwardo99 Expert Adviser
    I agree with all of that. And, it's still a flathead. But we are all Hudson lovers so flatheads are what we are stuck with. It is still a thing of beauty ... 
  • Frankvintagefullflowcom
    Frankvintagefullflowcom Senior Contributor
    edited October 2016

      aaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbccccccccccccc......testing.

    Plz ignore

    F

  • maasfhcenturylinknet
    maasfhcenturylinknet Senior Contributor
    Have run both 5" and 5-1/8 strokers.  No gains with the extra 1/8 in so went back to 5".  My 41 runs in the 12:50's quarter mile.  7:80 in the 1/8 mile
  • 50C8DAN
    50C8DAN Senior Contributor
    Thanks to everyone that answered by me and I hope others who read this thread.  This is the fun stuff we get to share on the forum!
  • HUDSONBROTHER1
    HUDSONBROTHER1 Expert Adviser
    A friend of mine had a 53 Hornet 4 door with a 5 1/8 stroke and a .060 over bore 308 ,Isky dual pattern cam,headers and twin H,hydro and 3.08 gears built by Clifford in the 60's for a dentist in San Diego.That motor would make that Hornet jump out of the hole in a hurry. That car surprised a lot of V 8 powered cars.I was told the car ran a best of 13.10 at Carlsbad Raceway but I wasn't there to see it The motor is resting under a bench in southern Oregon now.
  • molinelli1952
    molinelli1952 Member
    I'm buying my 1st hornet tomorow . It's a 52 4 door . 308 single carb with a hydramatic auto . Can I swap my single carb for the twin h setup ??? Been dreaming of my very own twin hornet since I helped my dad with his 54 back in the early nineties when I was 10. Now that I'm 31 the single carb is the only hornet that has been in my grasp and would definitely love it with a twin h power setup
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