Engine 351m/c6 In My 73 Stang. Any Hints Please.

Discussion in 'Classic Mustang Specific Tech' started by Walter Sparks, Nov 17, 2013.


  1. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    I have a 351 cleveland/FMX tranny that needs a rebuild. until I can get it done I have a 76 F-100 with a 351M and a C6 tranny. I think my headers and motor mounts will work, I also want to use my HEI distibutor and I have a new Melling HV oil pump, and a double roller timing chain, off my cleveland. will all of these work and What all will I have to do to complete this change??
    Thanks Sparkie
  2. horse sence

    horse sence SN Certified Technician

    Joined:
    Nov 30, 1999
    Messages:
    3,229
    Likes Received:
    455
    Trophy Points:
    123
    Location:
    Wile Coyote's stunt double
    the 351 M has a taller deck height than a 351 cleveland
    and if i remember right the motor mounts are different as well. the motor mounts and the bell housing is the same as a 429 or a 460 and not a 351 Cleveland. i have had a few 70s ford trucks with the 351 M ,boat anchors and gas guzzlers
  3. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    my advice, dont do it, the effort isnt worth it. you need the 429/460 engine and chassis mounts, the trans mount wont be an issue though. and then you have all the other niggling little crap that always pops up with an engine swap.
  4. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    So the motor mounts for the cleveland will not fit? Nor the mounts for the 351M truck? I figured I would have to shorten the drive shaft, but since I am installing the engine and tranny, I guess the only issues would be shifter cable and motor mounts and power steering pump/bracket. Any help would save me some time and frustration.
  5. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    the 351m mounts for the truck will fit the engine, but not the chassis, you need the big block mounts for that from a 71 mustang. the powersteering bracket can come from the truck as well. the shifter and the trans mount are going to be the same as with your 351c and trans, and as i recall the drive shaft should not have to be shortened, measure the tail shaft though to be sure.
  6. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    Thank you very much. The truck does not have power steering, so I will have to get that bracket from the junk yard. Anyone got some motor mounts??
  7. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    the chassis mounts are going to be very difficult to find for a couple of reasons;

    1: the 429was offered for one year only in the 71-73 mustangs

    2: it was not a popular option in 71.
  8. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    I found a new set of Mounts on ebay for $50 shipped. But I have decided to fix the old truck up and drive it for a while till I sell it then get a cleveland back in my stang. Thanks Guys you all probably save d me some major frustrations.
  9. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    i wouldnt use the word frustration when talking about swapping a 351m into a vehicle that never had it or the 385 series big block. its more of a t.a.r.f.u. heading fast into f.u.b.a.r. situation.
  10. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    Why would it be so difficult?? they did put BB engines in this body style, should fit without any body modifications. I do not really understand why it would be some hard thing to do.
  11. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    first again the chassis mounts, NOT the engine mounts, are very hard to find as few 71 mustangs actually had the 429 in them, thus you are going to have to fabricate the chassis mounts. second headers are not available for the swap so you would have ot fabricate your own. and even if you used stock exhaust manifolds, you would still have to have custom head pipes made because the 351c pipe wont fit, the block is as wide as the 429, and the 429 ones wont fit as the connection configuration is different. and depending on the configuration of the stock exhaust manifolds, you are likely to have clearance issues and that would probably force you to build headers for the car. the 351m/400 is sort of a bastard engine. the 400 was made by increasing the deck height of the 351c block to 10.3" and stroking the crank to 4" to create an engine to replace the 390 as the small "big block" engine for many cars and trucks. if you wanted something bigger than the 351, but smaller than the 429, you got the 400. the 351m was an even bigger bastard in that they used the 400 block and installed a 351w crank, essentially, and it wasnt engineered properly but rather slapped together so it was somewhat of a doggy engine. the only good things to use a 351m for are either a boat anchor, or to build a proper 400. and it isnt the body mods that are in question here, its all the little engine swap things, linkages, wiring, exhaust, etc. that make the swap in this case untenable.
  12. horse sence

    horse sence SN Certified Technician

    Joined:
    Nov 30, 1999
    Messages:
    3,229
    Likes Received:
    455
    Trophy Points:
    123
    Location:
    Wile Coyote's stunt double
    yup +1,not worth it
  13. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    ok chassis mounts, I misunderstood. Is that the cross member? I thought you were talking about motor mounts. Thank you.. for the warnings. I surely will not attempt the engine swap.
  14. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    the chassis mounts attach to the cross member. some are welded, some are bolted. if you have the engine out of your stang right now, check the location of where the engine mounts bolt to the chassis, that is the chassis mount that would need to be changed.
  15. Walter Sparks

    Walter Sparks Member

    Joined:
    Jun 22, 2013
    Messages:
    38
    Likes Received:
    0
    Trophy Points:
    7
    Location:
    Savannah Georgia
    oooo, I was not sure what that was. I will check it out. this is some very useful information. thank you for taking the time to help me understand.
  16. rbohm

    rbohm Founding Member

    Joined:
    Apr 13, 2002
    Messages:
    5,919
    Likes Received:
    177
    Trophy Points:
    104
    Location:
    tucson,az
    no problem, i always remember that i was once where you are now, still learning all kinds of new things. my learning curve though was always quite steep when it comes to cars.

Share This Page