Lower motor mounts?

Discussion in 'High Tech Retrofits' started by 71RS6SPD, Sep 25, 2017.

  1. 71RS6SPD

    71RS6SPD Veteran Member

    116
    4
    Nov 14, 2016
    I have a 71 RS with a GenI SBC. I installed 4.10 gears and a T56 from a 94 Camaro and it's great except I have a drive line vibration above 60 (not sure if it goes way at higher speeds.. only 70 so far). I'm running 4.10s so the shaft is spinning like crazy. After installing a new driveshaft did not solve it I did some research and just checked the drive line angles and I believe that is where the problem is. The motor is angled down to the back almost 6 degrees. Stock is about 3. Rear pinion angle is near 0. I have a nice aftermarket mount holding the trans in and do not want to cut the floor any further to move the trans up. Is there such a thing as motor mounts that will drop the engine a bit to reduce the angle? The car is a 71 and originally had a 2 barrel v8 so it does not have the 'big block mounts'. Do they drop the engine any lower? Before I adjust the pinion angle - maybe I can lower the motor?
    thanks
     
  2. badazz81z28

    badazz81z28 Veteran Member

    13,965
    91
    May 4, 2001
    Las Vegas, NV
  3. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

    .


    If you can't find an off the shelf mount that works for you, elephant ears are a fairly easy project, and you can get perfect engine placement.


    .
     
  4. Randy 81

    Randy 81 Veteran Member

    868
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    Oct 28, 2009
    Loganville, Ga
    Big Block engine stands are shorter, but the engine mount they work with is taller, so the assembly ends up at the same height as regular mounts. So that won't lower your engine. So Mrdragsters idea is a good way to go.
     
  5. badazz81z28

    badazz81z28 Veteran Member

    13,965
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    May 4, 2001
    Las Vegas, NV
    ^^^ why can't you use SBC motor mounts? You should not have to use them in pairs. The replacement mounts from places like energy suspension don't differentiate and are universal
     
  6. 71RS6SPD

    71RS6SPD Veteran Member

    116
    4
    Nov 14, 2016
    Thanks for all the reply's.. I cannot confirm that any combination of mounts and brackets will lower the engine. I wish it were an available solution but as like Randy 81 said same height? I searched for a while on elephant ears and found little - mostly mopar info and no parts for sale. I called gforce (crossmember) and they are sending me 1" of transmission spacer plates no charge. I have found engine plates. looks like plates and elephant ears would require a 1/4" crank pulley spacer to retain belt alignment. I guess elephant ears may just be trimmed plates. Will try moving the trans up first and see if vibes are gone - or move up the rpm range. It has a .5 overdrive - at 3000 rpm the driveshaft is cranking at 4500! That's around 95 MPH
     
  7. 71RS6SPD

    71RS6SPD Veteran Member

    116
    4
    Nov 14, 2016
    basazz.. Are you saying that I can use lower mount brackets for a bb awith the existing sbc mounts and it will line up and be lower? That's what I'm hoping for.

    thanks
     
  8. G72Zed

    G72Zed Veteran Member

    376
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    Sep 8, 2015
    Canada
    71RS6SPD, I am no expert, looking at this, add in the rear end offset that GM put in the second gen's, and you could be well above 9* total "compound" angle, toss in the elliptical effect only on one end without the self cancelling effect on the other, not good.

    To lower the engine in the frame, I have used a combination of Moroso solid frame mounts #62620 with the #62510 solid engine mounts, or even better the All Star solid engine mounts #38080 (.250 vs .188 thick) These frame mounts do not fit the original bolt pattern on all holes, but you can drill and bolt the others in. This would drop the engine 1.5-2 inches. It did on mine anyway.

    After that, I would look at shimming the rear end to get you "closer" to the "equal and opposite" on both ends with your angles.

    Again, just my 2 cents (1.6 Canadian)

    Hope this info helps.
     
  9. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

    .

    They definitely make a chevy model.
    I mentioned the ears so you don't have to use spacers like a full plate.
    A lot of my stuff don't have accessories holes in the head, so everything is mounted to the plate.

    You can also scallop around something if the plate is in the way a little.

    [​IMG]
     
  10. 71RS6SPD

    71RS6SPD Veteran Member

    116
    4
    Nov 14, 2016
    Looks like the Moroso 62620 frame mounts are no longer available. That was promising although I was not looking forward to getting in there to drill new holes in the sub frame. Still can't find sbc elephant ears.. I did find some other threads here that state 1/2" engine drop if I use the 70-72 BB/Z28 mount brackets (3964886 + 3982307 ) that require the narrow motor mounts.
    https://www.camarocentral.com/1970_1972_Engine_Frame_Mounts_Big_Block_Pair_p/enc-3.htm
     

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