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Best engine for a 51 Mercury

Discussion in 'The Hokey Ass Message Board' started by DjNeil, Jan 29, 2012.

  1. DjNeil
    Joined: Dec 29, 2011
    Posts: 210


    I pulled the flathead out of the merc and am looking into a replacement.
    I'm thinking of an early Hemi with tri power and all bits polished and shiney.
    There are not that many hemis in France (bar Facel Vegas)so am not sure about sump clearance and crossmember.
    Which hemi do i go for and who does the dress up bits for them. If not a hemi anyone got any suggestions.
  2. Flat-Foot
    Joined: Jul 1, 2010
    Posts: 1,699

    from Locust NC

    365 Caddy! Not much cooler than a Caddy powered Merc.
  3. Mine has a 500 Caddy.
    Pretty cool I reckon.
  4. A tub
    Joined: Aug 15, 2008
    Posts: 209

    A tub

    hate to state the obvious, but keep the original engine in it, id kill for a merc,let alone a 51 merc engine, , hope u have somewhere nice to store it or a rod to put it in, but choice of engine to change it, what bout 350( i know common),later ford v8,caddy motor is a beautiful thing, hemi's are pretty well my dream motor,y not olds motor(they are wide,great lookin motor come in gd size), capacity wise one last idea for ya here chev 348-409 w headed monster, plenty of stuff for chevs for the 348-409 from speedways even i believe
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  5. Stick with the stick flathead....Looks so right in that engine bay! If you have to switch I would go Caddy.
  6. ratty_aussie
    Joined: Jul 5, 2007
    Posts: 989


    Could agree more.
  7. studebaker46
    Joined: Nov 14, 2007
    Posts: 515


    all you guys who are so pro flathead have you ever even drove one they were really underpowered for big merc like the 51 so ivote for the hemi or the caddy. these cars scream big motors mho tom
  8. Zerk
    Joined: May 26, 2005
    Posts: 1,420


    If the question is "Which engine looks as good as the dressed flathead and has plenty of torque in stock form?", the answer would have to be Buick nailhead.
  9. Andamo
    Joined: Jan 10, 2006
    Posts: 498


    The way I look at it, the motor in your car is secondary to the looks of the Merc. Since you're in France and I'm sure finding American engines is tough, go with something that won't break the budget. My first choice is a Cad though.
  10. DjNeil
    Joined: Dec 29, 2011
    Posts: 210


    Thanks for that

    what manual box can i hook up to a 365 caddy motor and are they more expensive to build than a 500. Is the 500 a bigger block to fit in the Merc?
  11. 51 mercules
    Joined: Nov 29, 2008
    Posts: 2,597

    51 mercules

    A 331 or 354 Hemi! I have 331 in my 51 merc.I heard the 392 is a little wider and you have to modify the fender wells.

    Attached Files:

    Last edited: Jan 29, 2012
  12. 1950merc
    Joined: Jun 26, 2007
    Posts: 161

    from Butler, PA

    You pulled the best engine. Mercs are supposed to be low and slow, and there's just something about the sound of a flathead. I'm doing a 700r4 swap right now, and I could have gotten a free SBC, but I bought the adaptor for the flathead instead. I know there are plenty of critics out there, sorry to be one of them, but you asked. Good luck on whatever you choose. Looks like a beautiful start though.
  13. I'd vote for a Caddy mill.
  14. DjNeil
    Joined: Dec 29, 2011
    Posts: 210


    You have no idea how much I regret selling it's heart but I did and need to move on.
    Thanks for the nice words about the Mercury. I've had it 26 years now
  15. Gahrajmahal
    Joined: Oct 14, 2008
    Posts: 302


    I drove my 53 ford with flathead both stock and rebuilt with performance mods and the two speed fordomatic every day for three years in the 80's. it was 45 minutes to work 5 days a week. I drove it to Chicago for a work trip.
    All the motors you are interested in will be expensive to rebuild correctly, especially in France. I'm sure even the flathead will cost $$, mine did. Saying that, I would probably build the flathead but put a modern transmission behind it. That would have made my 53 fantastic. Oh, and the MPG with the flathead was not too bad, 15-20 mpg.
  16. jfrolka
    Joined: Oct 4, 2007
    Posts: 897


    That is one of the best looking 51's I have ever seen... 365" caddy with the 3 speed merc trans... Top that 365 with my 4x2 log manifolds :D
  17. 51mobster
    Joined: Jan 23, 2011
    Posts: 5


    Build her Ford tuff with Chevy stuff!!! I have a LS1 from a 2000 vette installed in my 51 Merc. Pulls great!

    Attached Files:

  18. straykatkustoms
    Joined: Oct 30, 2001
    Posts: 7,336


    Keep it simple small block Ford or Chevy. The hood will be shut most of the time, so
    just make it reliable. Love your Merc, Enjoy the cruise.

    Happy Trails, Mick
  19. desotot
    Joined: Jan 29, 2008
    Posts: 1,645


    I put a nailhead in my merc because it can also go slow.
  20. 29tudor
    Joined: Jul 16, 2007
    Posts: 303


    Stick with the merc flathead!
  21. kustomcar53
    Joined: Sep 23, 2011
    Posts: 26


    Im putting a flathead back in my '50. The flathead will do just fine for what it is. It's a Merc; who cares if it's slow? They're meant to look cool and sound cool, and nothing fits that bill better than a Flathead V8.
  22. Nailheads look cool.

    How about a Ford 312 with a T5?
  23. desotot
    Joined: Jan 29, 2008
    Posts: 1,645


    you know, if I settle the deal with this guy I know, my next merc is going to recieve a 57 merc 312, it's a beauty, has mercury script right across the valve covers.
  24. DjNeil
    Joined: Dec 29, 2011
    Posts: 210


    Can anyone post a photo of a period dressed Caddy motor.
    I saw one in a black 34 in LA last year that was up for big money(the car not the motor)I think it was a 500ci Caddy.
    What is the best manual box to stick behind the motor
  25. tattedfordguy
    Joined: Sep 13, 2006
    Posts: 1,362


    I say keep the flatty, What ever you do dont do a 350 or any chevy for that matter...
  26. Bad Bob
    Joined: Jan 25, 2006
    Posts: 23,768

    Bad Bob
    from O.C. Baby

    See if you can find a pic of Jeff Nepel's Caddy,in his Merc. Circle City did it for him. LOOKS AWESOME!!!
  27. Slag Kustom
    Joined: May 10, 2004
    Posts: 4,315

    Slag Kustom

    as my friend who daily drove his chopped merc with a flat head said. "its cool to everyone to see a chopped merc with a flat head but not cool to be the guy driving the chopped mer with a flat head."

    a early 331-365-390 caddy is an easy swap in a merc.
  28. Mine has a small block chevy in it, but I will eventually change it to a 56 Olds 324. I vote Olds, Caddy or Nailhead, in no particular order.

    Head over to Rikster's custom car photo archive to find pictures of the dressed Caddy in the Hirohata Merc. You can't go wrong with that look at all. Jeff Nepel's motor is tough looking also, although I don't have any pictures of it. Use the search function and it may come up.

    Attached Files:

  29. snaptwo
    Joined: Apr 25, 2011
    Posts: 696


    Having owned more than a couple '51 Mercs, the first being flatty powered , which was no slouch on the highway. I later put a 53 hemi with a Cad/La salle box, Fairly easy swap as I recall but I did have to do some sheetmetal work for the long bellhousing.Olds powered one came to me already badly done and I redid it using a slant pan 4 speed hydro and lincoln crrossmember, that proved to be a real redlight bandit with that short first gear and a 4:10 gear in the rear. Sold it then bought it back a year later with a blown motor ,stuck a tired 324 in it and sold it. The quality look of your car deserves a Hemi if you can find one but I'd use a post '54 motor with the short bell, you can take your pick on trannies.

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