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Technical Motor mount design for big block

Discussion in 'Traditional Hot Rods' started by Andy65, Dec 29, 2016.

  1. Andy65
    Joined: Jan 4, 2016
    Posts: 10


    Hello all-
    Im in the stage of my build where im building motor mounts and need clarification. Often times you see a deuce or model A where the fabricator has built his own mounts off each side of the frame rails. Obviously this works, but how does it not put incredible stress on the rails? i picture the weight of the engine trying to bend the frame rails inward and down. Does using a tubular crossmember that goes from side to side under the engine add any benefit? Any opinions or facts are greatly appreciated. Thank you in advance-
  2. Cross tubes always add strength.
    The cross tube mounts usually have a cheesy thin wall 1/2" tube to bolt the engine in, poof there goes the strength.

    Engine mount pad that cantilever off the frame do put some rotational force on the frame, but generally the cantilevers are short and the frames are boxed. Then the amount applied against what it can hold is minimal.
    You'd think someone should know what the hell they are ding when designing motor mounts right? I've seen super scary stuff go 130 mph with out much fuss.
    loudbang and squirrel like this.
  3. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,776

    Atwater Mike

    Ever see Tommy Ivo's single Buick digger? Semi conical pad around the top of main longerons (tubes) and a stainless hose clamp securing said mount. (!)
    NHRA inspection??? Always wondered about that. Use it on street? Naaaah...

    The BBC side mounts only appear to want to 'sag' when in static 'rest'. On acceleration, they lift the driver side appreciably, usually taking the left front wheel with it...
    Last edited: Dec 29, 2016
    loudbang likes this.
  4. Andy65
    Joined: Jan 4, 2016
    Posts: 10


    I agree- like I said, it obviously works, they are on lots of these old coupes. my 35 is going to be running a fat FE ford, So i want to make sure my car is built the safest/strongest without making it heavy. Nothing worse then closing one eye when you feed some coal to it.
    loudbang likes this.
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  5. anthony myrick
    Joined: Sep 4, 2009
    Posts: 4,446

    anthony myrick
    from al

    I have used these several times without issues but have wondered about the same question you asked motor mount 2.jpg
    I like this style even though it is the sorta the opposite of what you asked
    motor mount 3.jpg
    loudbang likes this.
  6. Here's some I made for a 392 hemi.
  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,196

    from oregon

    Works for me

    loudbang likes this.
  8. tb33anda3rd
    Joined: Oct 8, 2010
    Posts: 15,110

    1. Connecticut HAMB'ers

    i have a 430 buick motor. it has big gm motor mounts, a hefty bolt that runs through a rubber encased tube between a couple stout brackets. all held on by two 3/8 bolts into the cast block. seams strange doesn't it?
    David Gersic and loudbang like this.
  9. Andy65
    Joined: Jan 4, 2016
    Posts: 10


    Love these pictures! thank you much. that 392 photo proves that those rails are stronger than they look! I like the vintage look of that front saddle mount also. great ideas here
  10. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,776

    Atwater Mike

    I hated the Hurst mount for SBCs when I first saw it...(1958)
    But when I saw what it actually was, (FRONT ENGINE PLATE, with some excess material shaved off) I was sold.
    In an extreme performer, I'd like front-and-rear engine block plates, but for street I think George Hurst had it pretty well covered.
    @31 Vicky supplied a little geometry there, but still uses the Hemi as a cross member.
    Sound engineering. Note the poly Urethane bushings for 'shock' absorption, yet stiff control of lateral forces.
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 43,442


    I built these for my Chevy II, it has the original hat section frame rails up front. Just a few pieces of 1/8 x 2" steel strap, not much to it. Uses stock mount on the pass side, old Moroso solid mount on the driver side.


    The modern tubular urethane bushing mounts don't seem to fit with traditional looking cars, to my eye.

    (134 mph is as fast as this one has gone)
    loudbang likes this.
  12. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 5,746


    I like the look and positioning of the "Hurst style" saddle mount, but I've never seen anything similar for the FE motors. As long as you place the mounts somewhat close to any frame cross-pieces, it should handle the torque fine, and look good too. You're most likely boxing the frame, right? I think those tubular, crossmember style, engine mounts are probably made offshore now (think light weight and weak). What size is your FE? I am Butch/56sedandelivery.
  13. You like those- You should see the ones I made to stick a big ass v8 into a '59 Mercedes 190sl. The frame side needed to be removable too to get the engine out. Pulled a rabbit out of my hat with that one
  14. andis65
    Joined: Mar 13, 2013
    Posts: 1


    Butch/56sedandelivery - I scored two FE's recently, a 428 that is so intact that it even has the manifold heat shields still in place, then also a 406 6v engine that's in baskets, not sure what I'm going with yet... the car I'm building is a old 60's asphalt modified so keeping it "period correct " will land me a single carb engine.

    Sent from my iPhone using The H.A.M.B. mobile app
  15. greg32
    Joined: Jun 21, 2007
    Posts: 1,928

    from lemont,IL

    If you can run a saddle mount without clearance issues for steering, do it. Like in Anthony's pictures. Good luck.

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